There used to be a fairly comprehensive list of !Fedgroups at http://www.skilledtests.com/wiki/List_of_federated_Statusnet_groups but that disappeared with all the other resources on #SkilledTests
Many thanx to @TheFaico@LoadAverage.org for keeping the !Fedgroups up-to-date on http://www.skilledtests.com/wiki/List_of_federated_Statusnet_groups
The easiest way to boost signal is to join some groups of interest. There's a bunch at http://sn.jonkman.ca/groups and a reasonably comprehensive list at http://www.skilledtests.com/wiki/List_of_federated_Statusnet_groups