Specs and Data on Arduino boards and Shields

Has anyone thought of compiling information on the different Arduino compatible boards and shields.
The purpose for this question is that as an ardent tinkler and experimenter, I would love to take various boards and put them together for different gadgets.
A Tinkler compiled Library would be nice. Right now I need information on several boards but have no idea where to find information on them. The sellers do not supply any technical information
Can anyone assist?
A Forum or site for this would be welcomed
Thanks in advance guys

Shields: http://shieldlist.org/

Arduino compatible boards are supposed to be compatible in all respects.

The sellers do not supply any technical information

Reputable manufacturers do. Patronize them, not ebay.