It's hard to know how to respond to the events unfolding in Tibet. And it's hard on two levels. First, as an outsider anything I do or say is pretty much irrelevant anyway, but that doesn't justify walking on the other side of the street with eyes averted.
But more directly it's hard because of the attempt by the Chinese authorities to lock down every possible information source. It will come as no surprise that I don't think closing Tibet off from the rest of the world is a good idea - or indeed a good sign.
If the Chinese authorities were telling the truth about the violence allegedly carried out by Tibetans, then having external and independent observers is precisely what they would want. The fact that they don't means that their own stories must be viewed with suspicion, especially since they flatly contradict videos and images that have been smuggled out. Moreover, the fact that it won't even trust its own people - who seem inclined to condemn the Tibetans as "ungrateful" anyway - to judge events, and has blocked practically all external news sources, is yet more evidence that there is a massive coverup underway.
The question then is: What can be done? On a personal level, I think the least those of us with bits at our disposal can do is keep spreading the message that all is not as the Chinese authorities would have us believe and that there is likely to be violent repression going on behind that news blackout. The more outlets that point to independent news stories on the subject, and the more blog posts that restate these issues, the greater the likelhood that the Great Firewall of China will just buckle under the strain (or that China will just cut itself off from the rest of the world).
In terms of the bigger picture, I find pleas that the Olympics must go ahead regardless because politics and sport must be kept separate, or that otherwise the poor athletes will be penalised, rather naive. Sport is all about politics - about which nation is "better" than the others. If athletes really cared about sport for sport's sake, for the sake of achieving their best, they wouldn't go to such politicised occasions in the first place, but would be content with the million other sporting opportunities where they could excel.
So the question then becomes what good a boycott would do for Tibet. In direct terms, I think it would do very little, but indirectly it would show one thing above all: that somebody out there cares enough to say "enough is enough, let us at least do something, however symbolic." Maybe the threat of that will help concentrate the minds of the Chinese leadership; maybe it won't. But the more times the phrase "Boycott Beijing 2008" turns up on Google, and the higher in ranking that term occurs in searches for "Beijing 2008", the more they will at least think about it.
Update 1: Shortly after posting this, I've just come across this brilliant analysis of what the Tibetans are fighting for - and why they are fighting, even though it's hopeless.
Update 2: Typically sharp analysis on the same topic from Salon's Andrew Leonard here.