London is the capital of the Twittersphere according to a report on the state of the microblogging world.
London comes top of a list of the top Twitter 'cities' assembled on Hubspot's inaugural State of the Twittersphere report, although the manner in which the data is gathered may mean that accuracy can not be guaranteed.
Indeed, as HubSpot points out in the report: "Because the location field on Twitter profiles does not contain any structured data (Twitter does not require people to separate city from state or province, etc.) it is hard to do any detailed analysis on this data.
"However, the list of the top thirty most common phrases people type into their location section on their bio shows that Twitter seems to be popular in major English-speaking cities."
So, it's (not really) official, Twitter is the phenomenon of 2008, and the capital city of Tweet is London – narrowly ahead of USA, San Francisco and New York (which actually has three entries in the top 30, two of which are in the top 10).
Top 10 Locations on Twitter
New York, NY