|Map of tweets over morning of January 13 2012 using clima.me mapping tool.|
The above map was made a few hours later. You can see that the tweets concentration has moved somewhat from the roads to include the internal spaces of building. This illustrates the morning commute as mapped with twitter, as people moving from tweeting on the streets to tweeting in their offices.
These tweets from London that are not on the streets, significant numbers of the tweets in the lower image, show people using mobile phones in their offices, effectively bypassing any company social media policies and also providing data while at work.
This application of geography to twitter density shows the challenge mobile devices pose to company social media policy and security. Staff are clearly posing information from within their work places.