As many family history enthusiasts have already embraced Google+, we're already looking for ways in which we can make the service all about genealogy. Forget about how others may use it, we've got real work to do! We've got ancestors still to find.
One small thing we can do to let others know our research interests is to be sure our Google+ Profile includes mention of the Surnames or at the very least, the ethnicities we are researching. This can be done in one of two ways. Each profile includes an Introduction section which enables you to do some basic, but useful text editing. You can make things bold, italic, underlined, but can also embed a link, as well as include a bulleted or numbered list.
One quicker and more subtle way is to edit the section further down the page labeled Other names. In mine, I have included other names that someone might use to search for me through Google+ or a Google Web search. I have also included the Irish and Italian Surnames I am researching as shown in the image below.
I don't yet know how this text is indexed and whether these Surnames will serve as bait to lure someone to my page when conducting research, but it is certainly worth a try. As I learn more, I'll be sure to let you know.