I have looked on several website value evaluators. The most of them are undervaluating all sites and giving for ex to bitcoinmagazine.com 0$ value.
Others overvaluing them.
However this site seems to have the most realistic values. This might be over and under the real value by many evaluated sites but in the average it might be around it. Of course that doesn't mean that has the same value for everybody. The given estimated value must be regarded as how much would be worth by an auction and this as an average for the last year.
By MtGox the actual value may be much lower but as average value for the last year may be corresponding.
The brand names owned by Tibane might be higher than we think as they registered even Bitcoin as trademark:
http://www.reddit.com/r/Bitcoin/comments/2284ff/apple_rejected_my_app_because_the_bitcoin_icon_is/https://bitcointalk.org/index.php?topic=478377.0Another factor is that the automatic evaluator cannot see how much is a company worth behind that website and if the company is not generating its revenue from that website then the difference might be higher, like it is by Microsoft. The results could be better if the script would consider the value of the company behind that site and how close is that relationship between the site and the company.
In case of Microsoft the revenue is not generated directly from the website but it is still a very close connection with it and the company has a very high market value. So microsoft.com should be rated much higher.