Who's selling, who's buying at the Allen confab?Sun Valley, the quiet Idaho ski resort town, is about to get a charge from Silicon Valley. Allen & Co., the New York investment bank, has been holding an exclusive conference there for 25 years, but until recently, the invite list has been limited to old-media moguls. On the invite list for this year's conference, which kicks off tonight: Jay Adelson, CEO of Digg, the social-news website, which he cofounded with Kevin Rose. Here's why we think Adelson's on the list — and who else might show up.

Digg, of course, was infamously profiled in BusinessWeek last August, which assigned the company a value of $200 million. Most of Silicon Valley found that number spurious, but the credulous executives who run big media companies actually believe what they read in magazines. With Rose launching Pownce, a new Twitter-like file- and bookmarks-sharing service, and Adelson increasingly focused on Revision3, now would be a good time to offload Digg, whose noisy community of users is just getting more and more fractious.

Then there's Marc Andreessen and Gina Bianchini, the chairman and CEO, respectively, of Ning. Ning, long an ill-defined Web 2.0 startup, has found its purpose in life — making Facebook apps and other social-networking tools easier to build. Along with the purpose came $44 million in funding, in a round orchestrated by Allen & Co. And hence the invite. It's a bit early for Andreessen to sell, so we'll bet he'll content himself with hawking his build-your-own-MySpace tools to everyone besides Rupert Murdoch.

Why build when you can buy, though? Facebook, the former college-kid social network which has been growing spectacularly since it opened its doors to everyone last fall, has all the buzz right now, prompting Murdoch himself to diss MySpace. Facebook, of course, has been showing every sign of wanting to go public. The IPO option gives CEO Mark Zuckerberg, rumored to be attending Sun Valley this year, more leverage in any negotiation.

Rounding out the tech corps: Bill Gates of Microsoft; Yahoo CEO Jerry Yang, CFO Sue Decker, and even the gone-but-not-gone Terry Semel; and Mike Volpi, the former Cisco executive who's now running online-video startup Joost. Oh, and the usual old-media suspects.

There's one puzzling omission on the guest list, if reports are true: Quincy Smith, president of CBS Interactive. Smith is himself a former Allen & Co. dealmaker, which makes his absence curious indeed. Anyone know why people are saying Quincy won't show?

(Photo by briancaldwell)