Given the explosion in both social media and other types of sites require registration, the ability to get the same username across different types of services can be a very handy thing. When one considers the concept of a “web presence” and/or maintaining an online identity, getting a consistent username is quite important. Getting *your* username is almost as important as getting a web address/domain name.
I came across this handy site that automatically checks the availability of usernames/logins/handles for 145 social networking and bookmarking sites. The site is called namechk and it lists dozens of services that I haven’t even heard about.
Hopefully you will find the site useful.