[sorbus]

It's called a hellban. You can continue to read and comment, but no other users see your contributions. It's a really good way to deal with users who are posting spam (if you browse with showdead turned on, you'll occasionally see long dead posts filled with links), or trolls. If there were an indicator of a hellban, it would be somewhat ineffective, because then users would just make new accounts.

Anyways, looking at your comment history, there doesn't seem to be anything that deserves it. No spam, just a few lightly downvoted comments. But there's a lot going on behind the scenes, and most of this is automated, so you probably just ran into whatever indicators or metrics HN uses to determine whether to hellban users (or take away their ability to flag, or whatever else). The only way to deal with it is probably to email PG, if you want your old account back.