Hey guys, sorry for the delay in checking back--things picked up at work, and yada yada yada...
@Rhubarbodendrom: Thanks for PMing me and reminding me to check in here. Message Boards and IMs aren't on the list because while FB or Twitter are a single entity, IMs or Boards are amde up of dozens or thousands (respectively) different sites.
@Tora Ziyal and Shatinator: Just taking a general survey to get a sense of what social media people in which age brackets are most likely to use, and see if I can track generally over recent time what is trending and what isn't. No commercial reason. If you are super-concerned about giving someone this data or you think somehow that this is too much info, don't take it--it's a totally self-selected survey.
@Dimesdan: I agree, and wouldn't include Skype were I to do this again.
@Tora Ziyal and teacake: Sorry I didn't check back in sooner. But teacake, can't paint everyone with that brush anymore.
@Collingwood Nick: None of those, but all would be legit reasons for this. Hopefully you guys are willing to contribute your info.
I'll be happy to share the results if anyone cares to see them.