I dont know whether this is possible but I know with a lot of Messenger systems when you minimize it if somebody says something it flashes on the task bar. Many times I have forgotten that I was speaking to somebody after minimizing it only to find they have left. Is there a way to add this modification?

We're currently using a pre-built applet, so not really. On top of that, I don't know a method of making a browser button flash like Messenger - although there's probably some JavaScript trickery somewhere to make it work.