Apparently XVM has been changed so that you now need to log in on their website (with your WoT account) at least once every 14 days for stats to work.
Unfortunately, login seems broken for me. I get through the OpenID process on the WoT website, but on returning to the XVM website I get a message starting:
Cannot GET /login/checkSimple?openid.assoc_handle=%7BHMAC-SHA256...
Is anybody else having this problem?