Been wondering the same. The MSN plugin pulled all my old contacts (old addresses of people I still chat with and addresses of people I haven't heard anything of for years) from the server, and despite removing them from the server they now haunt me in the contacts list, looking out of place due to having nothing to merge with... I've tried removing them, but they always come back and even uninstall-reinstall of the plugin does nothing. Hmm, I wonder where does the plugin keep its cache of contacts? Is there a common location for data like that in Maemo 5?