The app is definitely useful for people who listen to twitter for marketing/customer support purposes. Your target user is probably someone who is using Tweetdeck or Hootsuite, rather than a casual user.

But then, both Tweetdeck and Hootsuite have similar functionality available. And they are very popular among prosumers and people who use Twitter for their work.

Probably the way to go for you guys would be to allow building some kind of custom search folders for Twitter, which people can then share. You can become a site where people come to discover the most interesting content from Twitter, curated by the people using the tools that you already have built.

Hope that makes sense.