Another cookie question

I was reading the recent cookie thread in this forum and it reminded me of something that has always puzzled me, not a problem, just a puzzle (and inquiring minds want to know!).

I always surf inside of Sandboxie so any changes in the original cookie will get wiped out. I can see why Wilders remembers me and I never need to log in, because I originally allowed a cookie to be created (surfed without being in Sandboxie). But whenever I read a thread the topic title will, as it should, change from bold to unbolded. Ok, that is expected while I am in that surfing session. But if I leave the Internet, dissolve the sandbox, come back in another session, Wilders somehow remembers that I read that particular thread, it is not bolded.

How is Wilders remember what threads that I have read? To anticipate a comment, no, I do not have Sandboxie set up to allow cookies thru.

Thanks,
Acadia

 

I think many forums store our "visited thread" information on their own servers. The cookie may be for automatic login purposes.