The influential breakingviews column thinks that Yahoo! (NASDAQ: YHOO) could use a shareholder activist (subscription required).

Citing its "discredited management team, a corporate strategy in need of a makeover, stock-price underperformance, a large free float with no controlling shareholder, cash on the balance sheet and many moving parts whose values don't appear to be adequately reflected in the Yahoo share price," breakingviews believes that an independent shareholder willing to take on an entrenched management team could unlock considerable value for the company's shareholders.

The question is how many shareholder activists -- who frequently prefer to target companies with more traditional, less complex business models -- would feel comfortable diving into a company that's been getting hammered by Google (NASDAQ: GOOG).

But the potential for value to be unlocked makes Yahoo! shares seem more interesting. Perhaps institutional shareholders could put pressure on the company to take more drastic steps to unlock value.

Companies that are good targets for activists are often good investments in general, with or without activist involvement. The first step for an activist in finding a good target is finding an undervalued stock. As Ronald Orol writes in an excellent column for TheStreet.com, "Good activist investors, at their core, are great stock pickers."

Oh and, if you haven't already, go buy Orol's wonderful book about activist investors, Extreme Value Hedging. It's one of the best, most original books about the market to come along in recent years.

Today's breakingviews praises the idea about which I posted last week: a merger between Citigroup Inc. (NYSE: C) and JPMorgan Chase (NYSE: JPM). (DealBook has also picked this up.) I thought such a merger would be a good way to get JPMorgan CEO, Jamie Dimon, into Citigroup's CEO slot.

Here was my rationale: "Dimon -- who was Citi ex-CEO Sandy Weill's right hand man until Weill fired him for not giving his daughter a good enough job -- would probably enjoy running a combined Citi-JPMorgan Chase. After all, after he left Citi, he took over Bank One, which merged with JPMorgan Chase. And then Dimon took over from its former CEO, Bill Harrison. But a Citi-JPMorgan Chase combination could land Dimon in Sandy Weill's old slot once such a deal closed."

Breakingviews said: "J.P. Morgan boss Jamie Dimon is the top pick of many investors to succeed Mr. Prince. Not only did Mr. Dimon spend more than a decade carrying Sandy Weill's bags on the shopping spree that built Citigroup, he also has made the financial-supermarket model work for his current investors. Citi shares are down 31% in the past four years; J.P. Morgan shares are up 24%."

With subprime meltdown and credit crunch in full-swing, there is a lot concern about how consumer spending will be effected. Just yesterday, Fortune's Geoff Colvin declared the American consumer tapped out, saying that the "evidence is powerful that, as incredible as it may seem, U.S. consumers are going to start living within their means again. Brace yourself."

So what does that mean? Well for starters, companies that depend on consumers living above their means probably won't fare too well: This could include many middle-market apparel stores, furniture stores, and other non-essential moderate-luxuries. An old couch looks like a lot more comfy when you can't pay your bills.

But investors seeking solace from the weakened consumer (and remember, you should only seek solace if you think this is likely to be a long-term shift. If you think it's temporary, you may want to buy on the bad news) may want to look toward luxury goods makers.

According to BreakingViews, "If there's a financial crisis going on, nobody told the world's luxury brands. LVMH Moët Hennessy Louis Vuitton, the French luxury group, and Burberry, the United Kingdom apparel designer, say their wares are flying off the shelves. At LVMH, third-quarter revenue grew 15% -- the fastest pace in years -- driven by handbags, watches and jewelry. Appetite for Burberry's tartan creations pushed its first-half retail sales up by 25%, as the group continued its march across the American heartland."

BreakingViews goes on to speculate that continued weakening in the US economy could hurt these brands, but I tend to disagree. Luxury goods consumers are well-positioned enough that they just aren't that vulnerable to the factors hurting lower- and middle-income consumers: rising gas prices, housing woes, etc.

At the opposite extreme, I continue to think that discount stores, especially dollar stores, could do well if the middle-class decides to tighten its belt. But the little luxuries that middle class shoppers like to indulge could find themselves squeezed.