This blog post from Penny Red is probably the most sensible analysis/response to the riots that I've read so far.
Months of conjecture will follow these riots. Already, the internet is teeming with racist vitriol and wild speculation. The truth is that very few people know why this is happening. They don’t know, because they were not watching these communities. Nobody has been watching Tottenham since the television cameras drifted away after the Broadwater Farm riots of 1985. Most of the people who will be writing, speaking and pontificating about the disorder this weekend have absolutely no idea what it is like to grow up in a community where there are no jobs, no space to live or move, and the police are on the streets stopping-and-searching you as you come home from school. The people who do will be waking up this week in the sure and certain knowledge that after decades of being ignored and marginalised and harassed by the police, after months of seeing any conceivable hope of a better future confiscated, they are finally on the news. In one NBC report, a young man in Tottenham was asked if rioting really achieved anything:
"Yes," said the young man. "You wouldn't be talking to me now if we didn't riot, would you?"
"Two months ago we marched to Scotland Yard, more than 2,000 of us, all blacks, and it was peaceful and calm and you know what? Not a word in the press. Last night a bit of rioting and looting and look around you."