If you’ve noticed more of those “click here for an incredible offer!!”-type tweets in the past few months, you’re not alone. There has been a significant increase in the number of scammers, hackers and other nefarious types on Twitter in 2010. Altogether, “crime” on Twitter has risen by 20% in the past year.

Content security and data protection firm Barracuda Networks Inc. has released findings from their 2010 Annual Security Report, which examines the state of security on the internet. In particular, this report looks at how much crime occurs on Twitter, and what types of information or actions the perpetrators are after.

The report examined over 26 million Twitter accounts to determine behavior and find any visible signs of hacking or malware spreading on Twitter.

They identified several different scams and security breaches that hackers were taking advantage of. For instance, in September 2010 there was a cross-site scripting hack that allowed those abusing the security hole to cause people to retweet without their knowledge. There have been banking trojans sent around the Twitterverse through tweets such as “ahah this is the funniest video ive EVER SEEN! [LINK]“, rogue antivirus malicious software links, and Bifrost Trojans all spread through the various URL shorteners that Twitter users know and love.

The crime rate on Twitter – that is, the percentage of accounts created per month that are eventually suspended by Twitter – increased from 1.6 percent in the beginning of 2010 to 2 percent by the end.

In addition to these crime findings, Barracuda discovered some interesting things about the nature of Twitter users in general. Out of every 100 Twitter users, 39 have between 1 and 9 followers. And about 79% of all Twitter users tweet less than once per day.