Facebook tried to buy Twitter. Google and Microsoft have been giving the red-hot Internet-messaging startup the eye. But we hear it's Apple that's closest to sealing a deal, possibly for as much as $700 million.

A source who's plugged into the Valley's deal scene and has been recruited by Apple for a senior position says Apple and Twitter are in serious negotiations, with the goal of unveiling a deal by June 8, when Apple's annual Worldwide Developers Conference launches in San Jose.

Twitter turned down a $500 million offer in cash and stock from Facebook, in part because Twitter's investors couldn't agree on whether Facebook's stock was worth as much as Facebook said it was. But Apple could easily pay cash. A source familiar with the thinking of Twitter's board says the company would be hard-pressed to refuse an all-cash offer in the range of $700 million. (Is Twitter really worth that? Since it's business is nothing but a fantasy at this point, any valuation, high or low, is a matter of make-believe.)

What does Twitter, an adorable but unprofitable startup, have to do with a hardware company like Apple? The iPhone is the obvious driver of the deal: The many iPhone apps like Tweetie that people use to post Twitter messages are hot sellers for Apple. But Apple gets the benefit of Twitter-addicted iPhone users whether or not it owns Twitter. And it seems like an odd cultural fit, since Apple's hardly known for its Web prowess.

That's where the deal makes a certain amount of sense, if you understand the particular culture of those who work on the Web. While Apple might have its pick of hardware designers and software engineers, Web developers are a breed apart — and they have balked at working at a company like Apple, which may look innovative to the world at large, but seems fusty and hidebound to the Mission hipsters who build websites. You'll hear the complaints: Apple's secretive and paranoid, resistant to the wide-open ways of the Web.

Twitter , of course, is open in both nature and spirit. Users overshare every last detail of their lives, while Twitter makes these updates available on its website, via RSS, and through third-party applications. Apple is surely realizing it needs to play in this world, and needs someone to show it the way. Is it coincidence that Apple has put Twitter executives on stage so frequently, or that it profiled Twitter as a "business" recently?

If Apple buys Twitter, it won't be about making money. It will be about making a statement. In 140 characters or less.

(Photoillustration via Virality)