Here's an interesting thought:
This is a screenshot from http://www.guardian.co.uk/news/datablog/interactive/2011/aug/09/uk-riots-incident-map, focussed on north London, around Tottenham Hale. There is a clear correlation between the high streets and the rioting activities, particularly around the A10 just south of Tottenham Green, where three separate serious incidents occurred on the main road.
The reasons for this concentration on high streets is likely to be severalfold. First, the ease of access by transport/car/foot. Second, for looting, high streets are more plentiful than suburban residential roads. Third, unlike an industrial estate (as exists close to Tottenham Hale station), a high street has lots of ways to escape and a crowd can break up very quickly as it scarpers up streets off the surrounding streets.
The Guardian is at present, in conjunction with the LSE, carrying out a study in which participants in the riots will be interviewed, and the 2.5million Tweets about the riots will be analysed http://www.guardian.co.uk/uk/series/reading-the-riots. It will be very interesting to find out how far the rioters traveled to access the place of rioting, as clearly everyone did not just step outside and begin rioting outside their own front door.