The organisers - they get their five minutes of fame.
The participants - get to say 'I was there man! I stood up!'
LJ - don't give a rat's arse as it has no impact on them whatsoever.
The only losers it seems are the people who'd prefer actual talking and discussion to pointless, childish gestures. This strike will have absolutely no affect on LJ whatsoever. Do people think they'll care that a proportion of the users won't post for one day? What exactly is it meant to achieve except make it look like fandom is throwing toys from the pram again? Pointing at something and saying 'don't want!' is hardly constructive.
As for the demands...bollocks is the best way of putting it. You can demand Basic accounts back all you want. It wasn't too many years ago there were no free accounts on LJ in the slightest. You HAD to pay if you wanted to use it. Look at all the other blogging sites, MySpace, Facebook etc...They all have advertising. LJ is a business and if they don't make money they go. If they're spending that money on improvements to the site, great. And it's not as if they charge massive fees to have a paid account. £10 quid a year for something you use so often? That's nothing!
I do think LJ need to act much more responsibly in how they release news like this and that's a definite issue that needs to be discussed and sorted. A pointless strike will do nothing towards achieving that goal and, honestly? I think it just paints the users in a rather immature light. Talking would help solve the problem, not silence.
But still, I'm sure it'll make the participants feel better.