http://www.wordstream.com/keyword-niche-finder/
The Free Keyword Niche Finder - WordStream's Niche Keyword Research Tool. Allows finding "buckets" of grouped keywords
http://www.wordstream.com/keyword-grouper/
The Free Keyword Grouper - WordStream's Free Keyword Grouping Tool - Good for PPC
http://www.ubervu.com/social-media-comparison/
Social media comparison - compare brands in social media - uberVU
You can see the referrals and traffic to an individual bitly twitter URL by copying the URL and adding + sign to it. For example, if you see something like this in a tweet: http://bit.ly/870Ry9 just copy it and paste it with the plus and you'll see http://bit.ly/870Ry9+. ; (from Seth Godin's blog)
http://www.semrush.com/
SEMRush - service for competitors research, shows Google organic and AdWords keywords for any site or domain