21% (One Fifth) of Twitter accounts are empty placeholders.
Nearly 94% of all Twitter accounts have less than 100 followers.
150 followers is the magic number. In a particularly interesting data point from the survey, Sysomos found that Twitter users tended to “follow back” all their followers up until about 150 connections. Then the reciprocation rate fell off dramatically, which seems to indicate that this number may be the crossover point where people shift from using Twitter for more personal use to using it more for “lifecasting” their thoughts and actions to a community of people who they feel varying levels of connection to.
A small minority creates most of the activity.
Half of all Twitter users are not “active.”
Tuesday is the most active Twitter day.
APIs have been the key to Twitter’s growth & utility.
English still dominates Twitter.
Twitter is being led by the social media geeks.
clipped from: blog.ogilvypr.com