Groupable, the online marketplace connecting groups of all types to local and corporate sponsors used their algorithm to determine the 10 most influential mom groups online. Groupable says:

"Based on our proprietary Groupability Index, influence ratings take into account Groupable’s sponsorship activity data as well as activity from variety of social media data points including Twitter, Facebook, YouTube, Klout Score, blogs, and podcasts."

And the top 10 are:

1. Work It Mom
2. Parent Hacks
3. Manic Mommies
4. Amazing Moms
5. Boston Mamas
6. Cool Mom
7. Rookie Moms
8. Moms At Work
9. Green Moms
10. Mommy Poppins

{source: Groupable}