Lots of services try and rate the reputation of online users, particularly in the world of online commerce. So it's not surprising that attention is being paid to rating users in the social networking space. Enter TweetGrade.

Purewire Inc. launched TweetGrade last week, calling it the authority in online user reputation on Twitter. "TweetGrade provides a quantitative assessment of a user's reach and influence in the Twitter community, and it helps people understand a user's online reputation, legitimacy and safety."

The company pointed to some of the scams encountered on the micro-blogging site as evidence that its service is necessary, such as a "Best Video" scam. "Attacks such as this make it imperative to know the reputation of those people with whom you interact online. TweetGrade assures this trust by providing evidence of Twitter account legitimacy, protecting users from malicious or illegitimate accounts that attempt to send spam or spread malware."

TweetGrade evaluates Twitter users based on their interactions on Twitter. The analysis is centered on a variety of inputs such as frequency and content of tweets, number of followers, number of those following and activity level. Users receive a simple letter grade that ranges from an "A+" to an "F" to verify their reputation on Twitter and are able to share their TweetGrade with the Twitter community with a simple push of a button. The company posted more information about its new service on its corporate blog.