The initial landrush to claim your Facebook username is over, with initial estimates of between 10 to 20 million usernames being claimed. Hitwise UK blogged that Facebook had its busiest day ever with the hype around the username launch with Facebook accounting for 5.17% of all web traffic. Will the second stage launch generate as much traffic for the social network as the next move is to open the floodgates for all the new Facebook accounts that were any accounts created after the username option was announced at 3pm on June 9th 2009.After 11:59pm (EDT) on Sunday 28th June, all new Facebook users will be able to register a username. These new accounts are required to have a verified Facebook account, which may require them to authenticate via mobile phone.Developers will have to wait a bit longer for username support as Facebook is still not allowing usernames to be accessible through its Platform API, where in the past applications were able to store UID's. This will not affect how you use Facebook apps on a day to day basis.An important point which makes the username feature different from email is that a period (".") does not count as a part of a username and does not make a username unique. Therefore, names like jamessmith55, james.smith55, james.smith.55... all constitute the same Facebook username. This limits the potential number of variations that are possible within the Facebook username system, so you should register your user name now. www.facebook.com/username/Facebook also not immune from hacking as it is not immune from its users having poor quality low security passwords has added help details for users who have had a username created for their account without their consent. If you need help because you facebook account has been hacked visit their help page.If you want more help with Facebook usernames visit their username help section.