What's the gauge of a stock's popularity? Conventional metrics would include individual ownership levels, trading volume, and perhaps even enrollment in dividend reinvestment plans.

However, if we boil this down to American Idol-ish levels of fandom, is there really any better gauge than discussion board activity?

Digging through discussions
Thanks to the data-mining efforts of fellow Fool Anders Bylund, I know that there are several publicly-traded companies that inspire hundreds of daily posts on the Yahoo! Finance message boards. However, there are only a handful of stocks that attract thousands of daily postings.

Over the past three months, for instance, the discussion boards of Bank of America (NYSE: BAC), Citigroup (NYSE: C), and Halliburton (NYSE: HAL) drew more than 2,000 posts on Yahoo! Finance daily. Among exchange-traded funds, Direxion Daily Financial Bull 3x Shares (NYSE: FAS) and its bearish counterpart, Direxion Financial Bear 3x (NYSE: FAZ), also clocked in over the 2,000 mark.

Is there a common theme among the chatter? There may be. Bank of America and Citigroup became poster children for the government-backed bailout of troubled banking giants. The Direxion funds are leveraged ETFs, aiming to triple the move up or down in the financial services stocks within the Russell 1000. For those who may have slept through the past year and change of market carnage, the recession started by the fallout in the financial services industry.

Halliburton is an oil and engineering titan, but you wouldn't know it from a cursory glance at the active message board. As a result of the company's past controversial field work in Iraq, the postings have more of a politically confrontational nature than an actual discussion of Halliburton's fundamentals.

So, is that it? Does notoriety sell? Bank of America and Citigroup were the neediest hands of the financial services fallout, grabbing $45 billion of TARP funds apiece. The Direxion ETFs are simply sector bets on steroids. There are oil-related companies several times the size of Halliburton, but it apparently makes the perfect icebreaker for an all-out debate on politics.

Thankfully, this may just be a Yahoo! Finance phenomenon. A look at the most popular stock-based boards on Fool.com reveals an entirely different set of companies. The three most discussed stocks on our site over the past 30 days are:

Now that's more like it. Berkshire Hathaway's high stock price may make it prohibitive for small investors, but folks love to talk about Berkshire frontman Warren Buffett, the best investor of our generation. Apple has been a market beater over the past few years, and it's always putting out a new gadget worth dissecting. AMD is perhaps more of a fire starter, as the underdog of microprocessors, but it's proof that you don't have to be the biggest to be the most talked about.

So, it's a good thing that investors aren't just drawn like moths to a flame war. However, since Yahoo! Finance still runs the biggest message board in the financial arena, it's also safe to assume that a lot of us aren't happy unless it rains.

Some other links to bank on: