Is that achievement still obtainable? I recently made a FB account and was wondering if I could still link it to my Subeta account.

Yes it is. :)

How do I link my FB account to my Subeta one?

I believe you have to be logged into Subeta and Facebook at the same time and then do stuff here. Then in order to get the achievement, you have to let subeta make a status message on facebook by you doing something on subeta. :o The list of things that work are on that page and you can pick which ones you want on and off, then pick one to do.

Very cool! Thank you so much!