It’s like the Silicon Valley version of the boy who cried wolf. The IAC-Flixster deal, that is. Earlier this month, TechCrunch and The Wall Street Journal’s “Deal Journal” blog reported on rumors that Barry Diller’s IAC was buying Flixster, a movie-fan web site that has gained a lot of traction thanks to its Facebook application.

Now I heard the same rumor, except this time those in the know said the deal was finally done, with a price tag of $200 million — of which $100 million is an “earn out.” Now that would be a handsome payout for Flixster, the San Francisco-based company that has raised about $2 million from Lightspeed Ventures and other angels. Even though it was a rumor, it still needed checking out. I called IAC and a spokeswoman was pretty categorical in denying the deal, saying:

To be clear, we have not acquired them and there is no deal in the works. Whatever information you have is completely inaccurate.

So there you have it. No deal.

The reason there are a lot of rumors floating around Flixster is because it has a direct bearing on the Facebook app community. A big-ticket exit (like the one rumored) would pump more hot air money into the Facebook ecosystem, which has yet to prove its money-making potential. We recently saw East Coast mutual funds pump $50 million or so into San Francisco-based Slide at a massive half-a-billion-dollar valuation (say what??!!).

Flixster has been using the Facebook app to basically pump up its growth. According to comScore, Flixster has about 15.4 percent of the total Facebook audience. The deal bodes well for other high-traffic (if not high-profit) apps on Facebook, such as iLike and Mesmo TV.

Jeremy Liew of Lightspeed Ventures (investors in RockYou and Flixster) had posted his thoughts on building a “business” based on widgets and Facebook apps. It outlines the challenges and opportunities associated with this “business.”