One of the items listed on the features page is the ability to use the email address instead of a username.
/Products/ActiveSocial/Features.aspx
Unfortunately I can't seem to figure this out. It seems I'm not the only one either as I found these three threads that asked the same question without answer.
/Community/Forums/tabid/68/aff/180/aft/46647/afv/topic/afpgj/1/Default.aspx#16500
/Community/Forums/tabid/68/aff/182/aft/46572/afv/topic/afpgj/1/Default.aspx#16119
/Community/Forums/tabid/68/aff/180/aft/46680/afv/topic/afpgj/1/Default.aspx#16751
Can one of the mods comment on this please?
