I just installed Jetpack from wordpress, figuring that it would handle several other plugins I have (after the deadline, wordpress.com stats) but it seems the stats portion doesn't work. I get the following message:
You are not a member of this site.
If you have just installed the WordPress.com Stats plugin, this error probably appeared because the API key entered in the plugin belongs to a different WordPress.com user account.
The owner of the API key must visit this site's stats page to grant access.
I checked my API key (got akismet to resend it) and it still matches.