While reading a blog post this weekend on tracking referral data from Twitter I came across a fascinating and eye opening stat about Twitter. The post pointed me to @TweetStats, a third-party site that provides stats on the top ten Twitter Apps. In their data they show that 50% of traffic comes from Twitter Apps. Some have even said that upwards of 80% of traffic comes from Twitter Apps.
The thing to note is that you may be receiving more traffic from Twitter then you realize. Since any traffic coming from a Twitter App will be shown as direct traffic in your analytics program. If you are using Google Analytics, you can overcome this by adding tracking parameters to your URL strings.