People here really should read the latest from Adbusters.
I'll also add - from reading various anarchist forums, etc., it appears that anarchists are generally perceiving the May Day violent/BB actions as a great and inspirational success. One can even find statements from anarchists who were previously arguing for cessation of BB who are now saying that they were wrong. So Adbusters seems to just be reflecting the general sentiment.
[A minor aside - one thing that bugs me - in each retelling, Occupy people keep inflating the number of people that they claim were at the NYC march - I've seen the number grow from ~8000 or 10-15,000 (estimates from Occupy-friendly sources I saw on May 1), to 20,000, to 30,000, and now Graeber is claiming 50,000-100,000.]
The cities and scale of BB actions on MayDay (specifically in SF, Oakland, Seattle, Portland, New Orleans, and NYC) could actually be predicted quite well based on 1. statements in advance in anarchist forums and related sites, announcing/calling for participation in the BB actions, in combination with 2. recent BB history in each of the cities. However, there were two significant exceptions (and I find these of some interest): smashy did not occur in Chicago (despite attempts to organize it) and was unexpectedly minimal in NYC.
With Chicago, the BBers appear to have had a numbers problem (and this was becoming clear from forum comments in the days just prior to May Day). They ended up having a BB of only 20-30 people. Moreover, Occupy in Chicago used marshals at the demonstrations ("there was no chance for action, between an army of cops on all sides and the occasional self-important protest marshal screaming in peoples' faces and making it clear that they would do their best to undermine or punish any unplanned activity"). Over the decades, I've been involved in many large demonstrations that have used marshals, and they really can tip the balance (especially when the number of violence-oriented people is smallish). Given roots in anarchism, Occupy groups tend to dislike using marshals (also, in case anyone's interested, here's a piece from the Communist Party of Great Britain, making the case for marshals/stewards - hat tip Jasper).
In NYC, there had been calls (in online forums) promoting May Day smashy. In the week prior to May Day, NYPD visited the apartments of a bunch of Occupy peeps (and pulled in yet others on old warrants). Apparently they were targeting people potentially associated with BB/the FtP "Wildcat" march, fishing for info, etc. I'm wondering if that NYPD intimidation essentially suppressed the BB actions. Also, in the Adbusters piece, I noticed the line that "And some Zuccottis have complained that union representatives actively blocked an attempt to lead the crowd toward direct action at the end of the night" (and I've seen another allusion to this elsewhere as well).