In this series, we take a look at the 25 stocks on the S&P 500 Index (SPX) that have turned in the worst performance during the past decade -- what went wrong, and what happens next.

In my day job, analyzing equities for Schaeffer's Investment Research, I'm always focused on one metric: expectations. They're not always easy to quantify, but investors' and analysts' expectations for a stock more often than not tend to drive its performance. For example, widespread skepticism makes it that much easier for a company's stock to bounce in the event of a positive development. And, on the other side of the coin, we have Unisys Corporation (NYSE: UIS) as a cautionary tale.

What went wrong? At number 7 on our list of SPX losers, UIS lost 86% of its value during the 10-year period that ended June 30, 2008. The shares peaked at $49.69 in September 1999, narrowly exceeding their previous high in October 1987. Shortly after tapping this all-time peak, Unisys would learn a harsh lesson about the danger of high hopes.

In the company's third-quarter earnings report, which hit the Street in October 1999, UIS admitted that revenue grew by just 4%, falling well short of analysts' expectations for an increase of 11% to 12%. Disappointed investors sent the shares plunging 37% over the course of one session, a sharp sell-off that surprised more than a few stock-market veterans. But, as Merrill Lynch analyst Steven Milunovich explained to The New York Times, "This company, under Larry Weinbach, has done nothing but meet and beat expectations. So when they disappoint, it makes it that much worse."

By most accounts, shares in Apple Inc. (NASDAQ: AAPL) should have gone well above $100 this week and held there. Instead, the stock trades little better than it did after its last earnings announcement in January.

Amazon.com (NASDAQ: AMZN) certainly reported a good quarter, but for its shares to be 70% higher than they were a month ago seems extreme. Google Inc. (NASDAQ: GOOG) and eBay Inc. (NASDAQ: EBAY) did well this earnings season and neither has seen anywhere near this kind of market performance.

Microsoft Corp. (NASDAQ: MSFT) has traded down most of the year. Observers would attribute that to comments that CEO Steve Ballmer made about expectations for the company's new Vista OS being too high. As it turned out, the expectations were fine. The market overreacted to Ballmer. The stock moved up on good Vista news.

General Electric Co. (NYSE: GE) is another company with strong earnings, but the stock has moved down over the last three months. That is until a Citigroup analyst raised a very old idea of breaking the company into pieces. In a day, the stock recovered all it had lost in the previous 90 days.

There is a theme in the trading of these four stocks. It's so simple as to be childish. Low expectations can give way to big yields. High expectations are hard to top. The markets expected the world of Apple. Apple delivered. The market saw no benefit in driving the stock much higher. The Mac and iPod did just great. The iPhone is on the way. No news.

Amazon has been pounded by Wall Street and the press for the last two years. The company lacks focus. It's in too many businesses. Jeff Bezos, the founder and CEO, spends too much money on marketing and building out the company's technology platform. That hurts margins. Of course, all of that is true until the day it isn't. That day fell in the middle of last week.

Douglas A. McIntyre is a partner at 24/7 Wall St.

We at Blogging Stocks are covering more earning reports of our favorite stocks than ever before. And you may have noticed the polls that have started popping up in our earnings previews -- yes, you now have the opportunity to show your stuff.

Before the earnings reports of each of the companies listed below, we'll give you a chance to make your prediction whether they will meet, beat, or fall short of expectations. Take a look at the news and the numbers at the links below, and make up your own mind. But the question is, can you and your fellow Blogging Stocks readers do better than the analysts and market experts? You'll never know unless you cast your votes.

Note: We'll update this post frequently, and point you back here from time to time.

• Intel Corp. (NASDAQ:INTC) reported 1/16. This poll is closed -- 52% of you agreed with analysts that INTC would beat expectations, and it did.
• Apple Inc. (NASDAQ:AAPL) reported 1/17. This poll is closed -- 86% of you agreed with analysts that AAPL would beat expectations, which it did.
• IBM Corp. (NYSE:IBM) reported 1/18. This poll is closed -- 75% of you thought IBM would beat analysts' expectations, which it did.
• Citigroup Inc. (NYSE:C) reported 1/19. This poll is closed -- 45% of you agreed with analysts that Citigroup would only meet expectations, but it came in just ahead.
• Motorola Inc. (NYSE:MOT) reported 1/19. This poll is closed -- 46% of you agreed with analysts that MOT would fall short of expectations, when in fact they met them.
• General Electric Co. (NYSE:GE) reported 1/19. This poll is closed -- 59% of you were more optimistic that analysts and though GE would beat expectations, but it didn't.
• Pfizer Inc. (NYSE:PFE) reports 1/22. This poll is closed -- 42% of you agreed with analysts that PFE would meet expectations, which it did.
• Advance Micro Devices Inc. (NYSE:AMD) reported 1/23. This poll is closed -- analysts had low expectations, but 42% thought AMD would miss anyway, which it did.
• Sun Microsystems Inc. (NASDAQ:SUNW) reported 1/23. This poll is closed -- a whopping 72% of you agreed with analysts that SUNW would beat expectations, which, no surprise, it did.
• Johnson & Johnson (NYSE:JNJ) reported 1/23. This poll is closed -- 59% of you agreed with estimates that JNJ would beat expectations, which it did.
• Yahoo Inc. (NASDAQ:YHOO) reported 1/23. This poll is closed -- sorry but 39% of you thought Yahoo would just meet expectations, when in fact it offered an upside surprise.
• McDonald's Corp. (NYSE:MCD) reported 1/24. This poll is closed -- 72% of you agreed with analysts and MCD's own forecast that it would beat expectations, which of course it did.
• eBay Inc. (NASDAQ:EBAY) reported 1/24. This poll is closed -- another strong showing, 70% of you, for eBay to beat expectations, and it did.
• AT&T Inc. (NYSE:T) reported 1/25. This poll is closed -- AT&T beat expectations again, as analysts and 72% of believed would happen.
• Microsoft Corp. (NASDAQ:MSFT) reported 1/25. This poll is closed -- a tough call, with 45% of you chosing beat and 40% chosing meet, but beat expectations MSFT did.
• Ford Motor Co. (NYSE:F) reported 1/25. This poll is closed -- despite low expectations, you were split 35%, 34%, 31% for beat, meet, and miss, respectively, and Ford did fall short.
• General Motors Corp. (NYSE:GM) reported 3/14. This poll is closed -- 52% of you thought GM will beat expectations, but after weeks of delays it finally came out that GM missed expectations.
• Sony Corp. (NYSE:SNE) reported 1/30. This poll is closed -- 59% of you agreed with analysts that Sony would miss expectations, and despite some good news, it did fall short.
• Merck & Co. (NYSE:MRK) reported 1/30. This poll is closed -- 68% of you were more optimistic than analysts and voted for beat, but unfortunately Merck's profits fell.
• Google Inc. (NASDAQ:GOOG) reported 1/31. This poll is closed -- Google easily beat expectations, as 59% of you predicted.
• Starbucks Corp. (NASDAQ:SBUX) reported 1/31. This poll is closed -- 64% of you voted for SBUX to beat expectations, but earnings were in line with them.
• Time Warner Inc. (NYSE:TWX) reported 1/31. This poll is closed -- 73% of you were more optimistic than analysts, but they called it -- TWX earnings met expectations.
• Boeing Co. (NYSE:BA) reported 1/31. This poll is closed -- 80% of you looked for Boeing to beat analysts' expectations, and it did.
• Amazon.com Inc. (NASDAQ:AMZN) reported 2/1. This poll is closed -- 48% of you looked for Amazon to beat expectations, and it did.
• Exxon Mobil Corp. (NYSE:XOM) reported 2/1. This poll is closed -- only 43% of you thought XOM would beat analysts' expectations, but it did.
• Cisco Systems Inc. (NASDAQ:CSCO) reported 2/6. This poll is closed -- 80% of you voted that Cisco would beat expectations, and it has.
• Walt Disney Co. (NYSE:DIS) reported 2/7. This poll is closed -- 65% of you thought Disney still had the magic, and indeed it did beat expectations.
• PepsiCo Inc. (NYSE:PEP) reported 2/8. This poll is closed -- the 87% of you who voted for Pepsi to beat expectations were too optimistic.
• Coca-Cola Co. (NYSE:KO) reported 2/14. This poll is closed -- two-thirds of you thought Coke would beat expectations again, which it did.
• Home Depot Inc. (NYSE:HD) reported 2/20. This poll is closed -- 57% of you expected HD to fall short, but it met analysts expectations.
• Wal-Mart Stores Inc. (NYSE:WMT) reported 2/20 -- Wal-Mart comes out ahead of analysts' expectations.
• Hewlett-Packard Co. (NYSE:HPQ) reported 2/20 -- HPQ managed to beat analysts' expectations.
• Whole Foods Market Inc. (NASDAQ:WFMI) reported 2/21. This poll is closed -- 58% of you expected WFMI to exceed expectations, but it fell short.
• XM Satellite Radio Inc. (NASDAQ:XMSR) reported 2/26. This poll is closed -- 57% of you thought XM would fall short of the consensus, but it squeaked out ahead.
• Sirius Satellite Radio Inc. (NASDAQ:SIRI) reported 2/27. This poll is closed -- 61% of you predicted Sirius would beat expectations, but results were in line with them.
• Target Corp. (NYSE:TGT) reported 2/27. This poll is closed -- 67% of you voted for Target to beat expectations, which it did.
• Dell Inc. (NASDAQ:DELL) reported 3/1. This poll is closed -- you were split on whether Dell would meet or miss expectations, but miss it did.
• Viacom Inc. (NYSE:VIA) reported 3/1. This poll is closed -- 41% of you thought VIA would disappoint, but it beat analysts' expectations.
• Berkshire Hathaway (NYSE:BRK.A) reported 3/1. This poll is closed -- 62% of you expected BRK to beat expectations, which it easily did.
• Oracle Corp. (NASDAQ:ORCL) reported 3/20. This poll is closed -- 58% of you expected Oracle to beat expectations, and it did.
• FedEx Corp. (NYSE:FDX) reported 3/21. This poll is closed -- 48% of you expected FedEx to beat expectations, but it fell short.

With some analysts souring on tech stocks, the question for investors and watchers of AT&T Inc. (NYSE:T) ahead of its Q4 report on January 25 is whether this telecom chameleon (formerly SBC, formerly Southwestern Bell and others, formerly AT&T) can repeat its strong Q3 results. That showing was based primarily on the strength of AT&T's wireless business. And it's still wireless that provides hope in some quarters, specifically AT&T's piece of the brouhaha over Apple Inc. (NASDAQ:AAPL)'s iPhone. Cingular (soon to be known once more as AT&T Wireless) will be the exclusive service provider for iPhones, which is bound to bring in boatloads of new customers for AT&T.

Some wonder whether giants AT&T and Apple can really get along, however. And the other big AT&T news in these days leading to the Q4 report is its new Unity service, a bundling of mobile and land-line services that is widely seen as an effort to stem the tide of customers going over to the cable providers.

AT&T rates a "buy" recommendation, according the Thomson Financial, with estimated earnings per share at 0.59, compared to 0.63 actual for the previous quarter, and revenue of 21.3 billion. The target price is 37.48 (it closed at 35.07 on Friday). MarketWatch and TheStreet.com agree on the 0.59 estimate, but place the target price at 38.50, with a fiscal 2007 estimate of 2.27 and an "overweight" rating.

Credit Suisse analysts recently raised their target price to $39 and fiscal 2007 earnings estimate to $2.54, as well as maintaining their rating of "outperform," based not only on the iPhone deal, but the completion of the merger with BellSouth as well.

What do you think? Are investors in line for another positive surprise from AT&T?

Also check out some other earnings reports that we're following, and let us know your thoughts on earnings expectations.

Everybody's back to hating Mr. Softie.

But this time the Redmond beast is feeling heat from investors and analysts and not from regulators looking to inhibit the bundling of software or consumers cursing security flaws or the bugginess of Windows.

Yep, now it is investors who are expressing their ire over quarterly financial performance and future guidance which, for the first time, overtly accounts for the piles of cash that must be spent building server farms among other things in order to meet the Google challenge. And such dissatisfaction is coldly evident in the recent price decline of 15% in five trading days since the release.

While negative investor sentiment accelerates, it becomes extremely easy to come up with reasons to avoid if you are not long and to sell if you are. Guidance is punk. Google is swarming. Apple circling. The Vista release has been pushed ever further out into the future -- so on and so forth ad nauseam.

Yahoo! matched analyst estimates, which typically is call for flat share price movement, and investors rallied around the stock, pushing it up 6% after hours.  Now the onus is on Google to come in with strong numbers.

Google rallied about 1% on the news of Yahoo! meeting earnings, but is still about 14% off it's mid-January high of 475.11.  Google missed estimates last quarter, so investors are likely a bit leery (prior to last quarter's miss, Google consistently trounced analyst estimates).

Google has been active, though, in expanding their offerings, recently bringing online a beta version of a Finance site and Calendar site in competition with Yahoo!'s incumbent offerings (Finance and Calendar, respectively).

Yahoo's Finance site is still the dominant player in that sector, but Google retains the lead in Search. Google Earth has garnered a cult following and is making headlines for its varied uses.  Both Yahoo! and Google have been on something of a spending spree of late, gobbling up niche companies in an assortment of fields.