I wouldn't really think that "we" (this forum) would qualify in any way for Wikipedia linkage, but, regardless of precedent, the unbelievable amount of information about the game present on the blog itself seems like it belongs in a wiki for the game. If it really doesn't fit the scope of Wikipedia, it won't really bother me if it gets removed, but it seems certain that the other site doesn't belong, and from the looks of it there has already been a bit of an edit war going on for a while. (One in which, a large number of different individuals have found and removed the link, and a single person continues to add it back.)
If you do manage to swing some sort of arbitration, I would suggest having them look at other contributions from that IP. When I was looking through the Dominion edits, I noticed he has also added a link to Ticket to Ride, and who knows where else.