I think it's still too early to talk about how useful Twitter was during this week's Mumbai attacks. The tendency is to assume it was more powerful than it actually was; Om Malik's take is the only skeptical viewpoint I've found so far. But we can say that Twitter has had a great month. Here's an incomplete list of Twitter's organizational/democratic/self-governance accomplishments in November. I'm probably missing some, so please add them as comments:

• Twitter VoteReport received 11,000 messages on Election Day regarding polling wait times, irregularities, and broken machines.
• A group of angry moms ended a Motrin ad campaign before it could even start, solely through Twitter. Here's Brian Lehrer and Virginia Heffernan with some background on this story.
• Mumbai, of course. The headline of this Forbes article captures the magnitude of this event for Twitter. Alexander Wolfe says this event "is likely to be viewed in hindsight as the first instance of the paradigmatic shift in crisis coverage: namely, journalists will henceforth no longer be the first to bring us information."
• My own Twitter circle--primarily government IT-types--was full of conversation about these events, and in the past day, we have begun to plan a strategy for deploying an internal Twitter clone to federal networks. I'm sure this same conversation will be had at many other large organizations in the coming weeks.