Hi,
I fully support Micha's explanation and reason why recent very strong chess computers (at least very strong compared to Millennium The King Element currently toping the list) can't enter the rating list. No significant enough competition to assess a rating.
As Tracy reminded it, I have a rating for the Centaur, and I am currently having the TabuTronic Proelium play in a couple of private tournaments to assess an early rating for it. But this is enabled because I enter chess programs in this tournament that are NOT chess computers, yet already owning a CElo evaluation at a consistent level, expected to be in the same league as the Proelium is. They are tough opponents for the Proelium or TCAII, averaging 2.600+ CElo, some over 2.700. I shared a game out of one of these tournaments, Proelium was facing HIARCS 6 on an emulated Pentium 75.
Nick is using a similar way of testing, with Shredder program used as a mighty opponent for the SenseRobot Chess.
But of course the Wike-Elo-Liste fulfills other goals, by design focused on chess computers only, not chess programs as an extension - and that's fair enough.
MfG,
Tibono