I suspect that it will take about a year or more for sufficient proprietary software to be added to the LJ code before it will differ enough from that of the various LJ clone sites to make any mass-migration of users to those alternatives difficult or inconvenient. That's when the real changes are apt to begin. I'll say that I hope I'm wrong, and that LJ won't be going down the road of so many other web services that have gone corporate. We should always hope for the best. After all, the LJ Social Contract is still there, though it is now called the LiveJournal.com Guiding Principles, at the behest of the corporate lawyers, as they disapproved of the use of the word "contract" in this context. (Apparently, this word now belongs solely to the legal profession. Sorry, Philosophy- you've been shat on again.) Maybe these principles will survive, and not be hollowed out, but that remains to be proven. I fear that Principal will eventually outrank Principle hereabouts.
As we don't know the terms of the deal, there is no way of telling how much power Brad, or anyone else connected with LJ, will retain in the expanded company. He claims to trust the new owners of the site not to make any substantial changes, and says that he would not have made the deal had he not done so. Fine. The question I'm asking myself is whether or not he has secured a strong enough position within Six Apart to ensure that they will not, in a year or two, sell their company, LJ included, for a big bundle of cash to, oh, say Yahoo, for example. Despite anything I may have said elsewhere, I'm pretty sure that the Trotts didn't buy LJ just for the free cookies. Cookies are tasty, but people with a taste for Venture Capital are seldom as fond of baked treats donated by admirers as they are of a Big Payday, and their pictures on the cover of Forbes. We shall see.
I hope that this is the last I'll have to say on this subject for a long time, as I find that the whole thing makes me a bit queasy. I want to get back to my usual maundering, and to quit staying up so late.