Sametime 8.5.2 now supports "widgets" and recognized names and numbers. If you have this capability, this means you can hover your mouse over an underlined name or number in chat history or an open chat window - or even in IBM Notes, such as in a Notes calendar invitation - to perform additional actions on that name or number. For example, you can click an underlined telephone number or name to select an option to start a call.
Here's how this looks in an open chat window:
IBM Sametime design
Matching: numbers X