Aha, to whom are you referring re reported speed? Obviously no human could produce the average speeds I am, but if you're wondering about anyone else on the CC team, well I think the speeds all seem quite likely, having heard from people about their type of cycling. [Edit - sorry, just noticed you weren't saying it was a CC person]
There's no real benefit to joining Cyclogs or the CycleChat team within it, apart from the community feel and the encouragement.
Oh, and congrats on your 10,001th post!