Well, as a member with over 10000 forum posts, I think they'd be hard pushed to determine that my profile was unused, despite being old.
Fair, I've had a few years off, but it's always been something I intended to come back to.
Also, wasn't the SSO login work years ago? My KeePass entry for this site specifically mentions SSO login.
I also seem to remember looking back at a number of my posts earlier in the year after a friend linked to them, and not seeing myself listed as a guest at that time but perhaps I'm mistaken.
Maybe @Grumpy_Mike, @CrossRoads, or another of the old friendly faces can advise exactly what happened.
(Do @mentions work on this forum now? I see note of it in my profile. Do I have to have more than 100 posts? 
)
Not fussed about the Karma but my post history would be nice to have back if this can be linked back up.