While resolving visitors ip adresses, look for the expression "bot" in the visitor's sitename. MSN bot visits could be detected this way, as they resolve to e.g. "msnbot-207-46-12-119.search.msn.com."
As of 0.5.5, MSN bot visits show up in the live plugin and are counted as visitors.
(In ) fixes #1238 - exclude MSN smartbot