On my Facebook account, it has taken about two years to get to my present level of "Friends." I must admit that I do not actively go out and solicit additional friends, I just wait for people to ask or invite only people I have some particular relationship with. Now, we come to Google+. Gone are the days of a slow growth in friends. With Google+ you get contacts every time you open the program. By concentrating on the genealogy community, I will shortly surpass the number of Facebook friends after only a couple of weeks of Google+.
Is this rapid growth good or bad? Time will tell. One thing I did find was to make sure anyone you add is really a potential member of your interest community. I had a "Notification" of someone who had added me as a member of their Circle and clicked to check it out. The first thing I noticed is that we had no contacts in common. I have not been adding anyone who did not share circles with someone I could identify as a member of the genealogical community. This particular "Invitation or Notification" turned out to be a highly objectionable spam site. OK, so Google+ has some (probably all) of the same issues as the rest of the Web. We need to be vigilant about being sucked into objectionable sites.
Despite this caveat, I think that Google+ could be another interesting tool to help support genealogy.