Recommendation for Group - Google, Yahoo, ???

[Black Landlord]

Some examples of spammers I've rejected:

Hello,

The following person would like to join the XXXX group:
Email address: acebae

Comment from user:
pls add me

Google the addy . . . easy one.

Another-

Hello,

The following person would like to join the YYYYY group:
Email address: a35mmlife

Comment from user:
Hiya... just a rider spreading the word of a project i put together...

Google "Obamaspoke"-- easy decision for a list with a purpose of connecting local riding partners.
A guy in California who thought he'd join every bike related list he could find to promote Obama.

Easy "approve":

Hello,

The following person would like to join the ZZZZZ group:
Email address: ______13 <________@gmail.com>

Comment from user:
I'm working at The Recyclery in South Evanston, a non-profit community
bike shop in South Evanston.