Nvidia (NASDAQ: NVDA), the big graphics chip maker, warned on profits. It was an inauspicious beginning to the earnings season for tech stocks. Many of the world's PCs use Nvidia chips. One of the reasons the company gave for its trouble is slowing demand combined with lower prices. The news was considered so bad that NVDA shares fell over 20% after hours.

According to MarketWatch, the company "expects its second-quarter revenue and gross margin to be lower than its previously announced forecast. The company now expects revenue from $875 million to $950 million." The consensus among analysts was that the company would have revenue of $1.1 billion.

Because the firm's products are so closely associated with PC sales, shares in other chip companies like Intel (NASDAQ: INTC) and computer makers like Dell (NASDAQ: DELL) are almost certain to be viewed as candidates for earnings downgrades of their own.

Nvidia's forecast could be the start of a very hard quarter for tech companies. And they may have been Wall Street's last significant hope.

Douglas A. McIntyre is an editor at 247wallst.com.

Yahoo!, Yahoo!, what did you do?

While I busy myself composing a nursery rhyme about Yahoo!'s deadly warning of an hour ago, I'm looking at the red numbers on my monitor. (What rhymes with "Project Panama"? Ooh, I can just rhyme with "unforeseen delay.") Yep, Yahoo! Inc. (NASDAQ:YHOO) is not looking good, down $3.57, or 12.3%, and flirting with its 52-week low of $24.91. Google Inc. (NASDAQ:GOOG) down 4%, or $16.54, to $398.15 (break on through to the other, other side!). eBay investors are slamming their portfolios, too, selling off eBay to the tune of a drop of 82 cents, or 3%, to $26.02.

Yahoo!'s position as bellwether certainly has a storied history; I remember oh-so-well those heady days in early 1999 when I sat in Jeremy Siegel's finance class at Wharton and watched Yahoo! soar to ever-dizzier-heights, rising and falling $100, $200 a share in a single day. It was crazy, and the company always lead the market. That was long before the advent of a public Google; and it's interesting to see how Google and Yahoo! are interacting now that the two of them share a sector on the NASDAQ.

Yahoo! is to blame, that's for sure. It's the company's failure to grab revenue from the ever-luscious but hard-to-handle local classifieds. It's the terrifically unreliable growth. More than anything, it's the "confusion and delay" caused by the unknown future of Project Panama.

It's all Yahoo!'s fault.