Data Science Groups on Linked In I am interested in joining some Data Science Groups on Linked In.  The relevant list is long.  I don't think it is to my advantage to join all, but I am not sure how to evaluate the individual group's potential to elevate my career.  

Is there some clear criteria for which I can evaluate potential groups?
You are limited to
50 groups.

KDNuggets used number of members, growth rate, number of conversations and member engagment in their 
analysis of data science groups.