Financial terms weren’t disclosed, though Kommersant reports the deal to be worth some $30 million. The sale comes about a year after Six Apart and SUP allied to bring LiveJournal to Russia, where the platform quickly gained a lot of traction. Today www.livejournal.ru accounts for 28% of LiveJournal’s overall audience. As SUP CEO Andrew Paulson once said, “LiveJournal is the ‘blogosphere’ in Russia.”

The acquisition, then, would appear to make perfect sense. Six Apart unburdens itself of a tiring distraction and SUP gears up to transform LiveJournal into what its previous owners could not. “This is pretty cool because [SUP is] ridiculously excited about LiveJournal, and [has] been for a while,” writes LiveJournal founder Brad Fitzpatrick. “They want to throw a lot of resources at LiveJournal in terms of product development and engineers. ‘LiveJournal.com, Inc.’ now stands alone again, focusing on nothing but LJ. “

Bebo and Six Apart are nice additions, but it’s MySpace that will bring quite a bit more heft to this effort–an addressable market of some 70 million active monthly users, at last report.

Who’ll next join OpenSocial? Will it be Facebook? CEO Mark Zuckerberg’s likely puzzling that question out at this very moment as he waits for an invitation to join–which apparently hasn’t yet been extended. “Despite reports, Facebook has still not been briefed on OpenSocial,” the company said in a statement. “When we have had a chance to understand the technology, Facebook will evaluate participation relative to the benefits to its 50 million users and 100,000 platform developers.”