http://blogoscoped.com/forum/154888.html
says it's old but it's less than a day old

Yes, I too have noticed that some thread are soon locked as old despite being very fresh.

Will look into this, thanks guys.

Thanks Philipp~ Is there any way to manually unlock them?

There is both a way to manually lock a thread (if it's new, but sees a high amount of spam, for instance), as well as to manually unlock a thread (if it's old but still has an active discussion)...

"before thiswas blogged." Typo haha