A friend recently turned me on to this site – namechk.com – where you can check your username availability at scores of social networking sites. It’s super simple. Just go to the site and type in your business name, domain name (i.e. insightdesigns – without the www or .com), or personal name (i.e. bethkrodel – no space between first and last names), then click the “chk” button. The site then checks 72 of the most popular social networking sites (including Facebook, Twitter, LinkedIn, YouTube and MySpace) to see if anyone is already using that username.

For some of you, it might just be interesting to see who else is using your name. For others who care about controlling, promoting and protecting your online identity, it’s probably worth going through the hassle of registering your branded name across all social media sites. (For example, we at Insight Designs wouldn’t want someone else posting questionable videos on YouTube under our name or making derogatory comments on Twitter under our sig. You probably wouldn’t want that either.)

My friend Jerry Nordstrom, CMO of San Diego-based Lead Discovery, says not registering your name with social media sites today is “akin to not registering related domain names for your business in the 90’s.” The cool difference is that in this case the registration is free (meaning the social networking sites don’t charge you to sign up as a user).

And if you don’t have the time to do the registration work yourself, there’s a site – knowem.com – that will fill out the registration form on 120 social media sites with your username and information for $64.95.

One drawback — extra email. Whether you do the registration yourself or you pay a service like knowem.com to do it for you, you’ll get emails from almost all of the social media sites. Be sure to go onto each site and edit your preferences to ensure that you’re only getting the emails you want.