One of the new features in the latest ClearContext release is the implementation of suggested Topics. ClearContext analyzes your email patterns and suggests Topics based the message sender. Change the number of suggestions made via ClearContext > Options > Preferences > Topic Options.
If upgrading from a previous version of ClearContext, go to ClearContext > Options > Analyze Contacts and re-scan your email history. This will help ClearContext give accurate Topic suggestions when filing.