I am a Ffffound.com user, and I have two followers.
How did these people start following me, and how do I follow them back?
I just took a look at the fffound.com site. Unfortunately, registration is by invitation only, so I can't join to see how things work.
However, I notice that the web sites of some contributors are posted on their pages. I suggest that you go to the web sites of the individuals that have followed you, obtain their email addresses, if possible, and ask them how they followed you.
I've found the answer to this, so I'll reply, hoping this could help someone out.
The way one starts following other users is by liking their images. The system automatically notes down who you will be interested in following, and these user's images are pushed to your suggestions.