Looks like Teacoin has been rather abruptly delisted at Tradesatoshi:
It was on the delisting list ages ago - my "Windows wallet?" post from April 15 was because of that. They delayed most of that batch of delistings because of all the KYC ("We'll steal your money!") problems they're having.
Hmm, well it's not showing at an earlier date in the news, and I checked my email from around March onwards and there's been no mention there either.
A heads up would have been nice, as I had a balance on there.