Interesting thread. As a reader of games reviews (with a little experience of writing them too) I've always felt that one of the most useful and trust-cultivating features a review site can offer is a prominent 'reviewer's track-record' section embedded in every review.
This section would contain info on and links to the previous 5? 10? reviews that writer had produced for the site. A hypothetical example:
I'm reading a review of Operation Bent Javelin on
www.grogland.com. It's written by Ivor Chiponmyshoulder. One click away from this review is a list revealing that Ivor has written 13 reviews for Grogland of which the last 10 were:
Storm Over Suez (Detonation Software) 88%
Kursk '43 (Powder Monkey Games) 15%
Mailed Fist (Detonation Software) 95%
Viking Raiders (Powder Monkey Games) 23%
The Washing of the Spears (Hex House) 55%
Vimy Ridge (Hex House) 62%
Spitfire Summer (Inferno Interactive) 68%
The Battle of Omdurman (Detonation Software) 87%
Waterloo 3D (Inferno Interactive) 71%
Austerlitz 3D (Inferno Interactive) 73%
(In the event that scores aren't used then links would have to suffice)
Naturally I've played a few of the titles on this list and can compare Ivor's analysis with my own. In no time at all I can see whether Ivor is a reviewer I can trust and relate to.
Speculating about a site's bias or lack of it is ultimately pointless as nothing can ever be proved. At the end of the day the reviewer's (ergo, the site's) track-record tell you everything you need to know about their trustworthiness/competence.