Imeem is laying off a quarter of its 80-person staff, PaidContent reports. The music-centered social network has been more adept than many of its rivals at navigating the cutthroat music business. But one of its backers is Sequoia Capital, the ruthless VC firm which has ordered its portfolio companies to slash expenses. Imeem is also seeking to sell itself, with the help of investment bank Montgomery & Co. Imeem may be better than most digital-music startups — but it is still a digital-music startup, faced with fickle consumers, thin margins, and antagonistic partners in the record labels.

MySpace Music, a joint venture between the News Corp. social network and music labels Universal, Sony and Warner,finally launches next week, says Fortune, though it still won't have a CEO. MySpace users will be able to listen to and organize playlists full of songs from all three music labels for free. (EMI is the lone holdout, which means no coldplay.) Playlists will include affiliate links to Amazon.com's MP3 store. MySpace CEO Chris DeWolfe says ad revenues and song kickbacks are going to save the music industry, replacing lost CD sales.Imeem CEO Dalton Caldwell, whose company already offers a similar product,

Rapper turned startup advisor MC Hammer recently swanned through the San Francisco offices of Imeem, praising the music startup for its "beautiful women." Why are startups so prone to opening their doors to the man formerly known as Stanley Kirk Burrell? Attention from a pop star, however marginal, however faded, provides the insecure geeks who run these companies with priceless external validation. Their work must be important — why MC Hammer came to our offices and ogled our female coworkers! The sad thing is that Burrell has been working the startup circuit since the last bubble.I remember when he swanned into the offices of eCompany Now, a long-gone tech-business magazine I worked at, in 2000, camera crew in tow. They were working on a documentary about a "startup" that never materialized. There you go: Even that part of Julia Allison's business plan isn't original.

Little has been heard from Slingshot Labs, the startup "incubator" News Corp. formed in February, in the months since its creation. The $15 million fund for spinoff ventures did succeed in keeping MySpace CEO Chris DeWolfe in place: We hear that he made it a quid pro quo before signing a new, lucrative contract with Rupert Murdoch. He's not the only MySpace employee Slingshot played a part in keeping down in Los Angeles. We hear Nick Granado, a top engineer behind MySpace's iPhone version, first flirted with a job at Facebook, then worked briefly at Imeem, before getting lured back with a gig at Slingshot.

Snocap, the company started by Napster creator Shawn Fanning, has been acquired by social network Imeem. What the fate of Fanning's sophomore effort proves: There may be second acts in the Valley, but they're usually not any good. Imeem had been using Snocap's digital registry to identify uploaded music for over a year. It also reunites a number of original Napster employees, like Snocap COO Ali Aydar who will be the new VP of operations at Imeem. Snocap had been rumored to be for sale for some time after slashing jobs. The 15 remaining employees will be absorbed into Imeem's growing San Francisco office — which added the staff from Anywhere.fm earlier this year.

Allfacebook.com is reporting a rumor that Facebook will take on Apple's dominant iTunes by introducing its own music store. Few details are provided, save that they are actively looking to hire someone to head the project and discussions with studios have been ongoing. Music applications such as iLike are popular on the social network, and digital music is a natural fit with the site's original college-kid demographic. But could Facebook really pull this off? At this point, we don't really know what a Facebook music store would be. We do know, however, what it's not.

Dalton Caldwell, founder of the little-known social network and media sharing site iMeem, is in the news because Warner Music has dropped a copyright suit against his company Instead, Warner has granted Caldwell's users free access to the label's entire music catalog in exchange for a portion of iMeem's advertising revenue. Caldwell may not be the most powerful social-network CEO, but he's certainly the scrappiest, and this is just the latest example in his history of responding well to adversity. You could learn a lesson from him Or five lessons, actually:

Everyone knows that Caterina Fake and Stewart Butterfield were made for pretty photos. Flickr's founding couple does a great job sexing up the cover of the latest Newsweek as the poster children for the new feel of the Net. In case you missed the last three years of what Newsweek calls "the Living Web," here's an intro to the cast.

One SXSW party invite stands out today — social IM site imeem (or, properly, "imeem!" but that sounds like a Broadway show) is ending SXSW Interactive SXSW Film (what the hell, imeem?) and kicking off the Austin fest's music leg with a big Tuesday-night party. And they booked a little band named Sleater-Kinney.