Consider developing new services and products for your clients for competitive intelligence, brand management, and reputation monitoring.
Here are some tools.
Addictomatic is a federated search engine that pulls results from live sites such as Google Blogs, Wordpress, Technorati, Twitter, YouTube, Flickr and much more.
OneRiot crawls the links people share on Twitter, Digg, and other social sharing services.
CrowdEye

Backtype is the only free tool I know that searches blog comments.
There are also fee based products such as Radian6 and Attaain that offer powerful features to research, analyze, engage, and tract activity on real-time sites. Consider starting out with some of the free offerings mentioned here and dazzle your clients with the information you can deliver.