I found this quite useful for looking up what people were saying about my blog on twitter. Or seeing who was re-tweeting my tweets on twitter. http://TwitPipe.com You can simply plug in some keywords and easily see what people are saying.
Another tool that tweeple may find helpful is http://twittley.com/ it is a social bookmarking site that integrates twitter to spread your domain name around. I recieved a couple hundred hits after placing my site here not a bad little tool.
Your welcome ^^ Also if your looking to try and find more followers here is a directory which everyone in it follows back>> http://www.ifollowback.com/register.php and a viral system that really helps get you followers>> http://ViralFollowers.com/makemoneyfree21/vu
The market research services might be stopped eventually. This is how twitter proposes to make it's money. Just so you know...