I did donate to the site, but if you look closely there is no set amount the 20$ is only a suggestion unless thats changed in the last week.
truthfully RCU is a much more fast paced site,with alot more members.
many of the questions I have had have been answered in a matter of hours and been quite helpfull.
when I have made a posting on RCSB sometimes it's taken weeks to even see something in a thread and alot of times there has been nothing pertaining to my question at all.
it's a volume issue RCU can sell alot more add space and generate more profit.
the volume of information on RCSB and the method of catagorization is a huge help and well worth a couple of bucks for usage.