Almost three quarters of Twitter's 100 million accounts are unused or responsible for delivering malicious links.
In the 2010 mid-year security report from Barracuda Labs, it analysed more than 25 million Twitter accounts, both legitimate and malicious, and found that true Twitter users (a user that has at least ten followers, follows at least ten people and has tweeted at least ten times) tweet more often and as casual users become more active, malicious activity increases.
It determined that only 28.87 per cent of Twitter users are ‘true Twitter users', and the Twitter crime rate - the percentage of accounts created per month that were eventually suspended for malicious or suspicious activity, or otherwise misused - for the first half of 2010 was 1.67 per cent.
The report also found that Google distributed the most malicious links of four of the most popular online services Bing, Twitter and Yahoo, with 69 per cent of its results poisoned when searches on popular trending topics were performed.
The analysis reviewed more than 25,000 trending topics and nearly 5.5 million search results. The average amount of time for a trending topic to appear on one of the major search engines after appearing on Twitter varies tremendously: 1.2 days for Google, 4.3 days for Bing, and 4.8 days for Yahoo.
Also, over half of the malware found was between the hours of 4:00am and 10:00am GMT and the top ten terms used by malware distributors include the name of a NFL player, three actresses, a Playboy playmate and a college student who faked his way into Harvard.