Google has given clear signs where it is heading with the whole social network phenomenon by sprucing up Gmail with a "Themes" functionality.
Google has introduced themes to Gmail in a bid to shed its boring white look and allow users to customise their experience; themes functionality is already available on iGoogle and it was only a matter of time before the Search giant rolled it out on its second most popular property.
More than 30 new themes have been rolled out (including a surreal green on black 1980's Courier theme called Terminal) and can be accessed through Settings > Themes and it may not be long before Gmail allows its own users to come up with their own designs.
Gmail has probably surpassed the 100-million user barrier (it reached 87 million users in October 2007) and could very soon integrate more social network functionality like following your friends, status updates (through Gtalk), pictures (through Picasa) etc.
Expect Gmail Labs to be the play ground where Gmail engineers will experiment their next features; Google launched seven new features for Gmail last month and there's nothing to indicate that they will slow down.
In comparison, Facebook has 120 million active users worldwide.