Should I follow this person back?

A question from one of my “Pinterest Done 4U” clients:

Well, this was sort of a surprise.  My first unknown follower.  It is the best etiquette to follow back?

I looked at the Pinterest account that followed hers (she has three accounts following her naturally. One is her personal account, and two are mine). This is what I saw:

1. He is active (lots of pins, lots of boards), so maybe.
2. All of his boards are “group” boards with multiple pinners. (Group boards have the little logo of three heads, next to the # of pins.)
3. This could be a Pinterest spam account, although the boards look legitimate enough.
4. You don’t have to follow him back today.  You can wait.  He won’t notice your pins in the flow of pins from 17,000 people he’s following.
5. You can follow some, rather than all, of his boards.  OTOH, none of his boards are in your industry.

All of that said, I might sit tight for a while and not worry about him. With the number of users he has (> 3000), he won’t notice whether you follow or not.