But apart from that, you have, for some reason, been "hell-banned". Without seeing your posts and/or comments from around the time it happened I can't offer any suggestions or advice as to why it happened. Do note that sometimes it happens by accident. It happened to me the other day, and in a reply to an email I sent asking about it, PG said I'd been "fat-fingered" by accident.
With regards the algorithms, I have no inside knowledge, just deductions based on what I've seen and some experiments I've run. However, if you consistently get flagged, or get downvoted vigorously, I suspect there is an automatic hell-ban, possibly preceded by a "slow-ban" (wherein everything slows down and responds like molasses for a while). If PG was being completely honest (and I'm not suggesting he wasn't, but as a mathematician I tend to try to cover all bases) then some (and perhaps all) hell-bans are actually performed by the moderators, possible in response to flags thrown up by automated detection systems.
As an aside: Do you understand the effects of flags, downvotes, and their differences?
So if you want to know more, perform searches for "hell-ban", "flag", "downvote", "dead", and combinations thereof. You'll find plenty of discussion, and considerable complaints. For one, I think that PG has done remarkably well in keeping HN civil (although clearly not perfect) in the face of popularity, and the occasional false-positive and draconian measure might well be the price paid.
I've never seen this sort of thing happen. Were they "dead on arrival"? When you posted the links, did you then check to make sure there was a reply comment box? Did you log out and see if they were there? Did they die after some time?
There are web sites that are banned, and links to them are simply never alive. I don't know the list off-hand - you can find them with a search. However it's certainly true that techcrunch isn't one of them, so that doesn't explain everything.
I've been on this site for a significant time, and I can't explain all your links being dead, comment-less and point-less. You might send an email to PG and ask, but be I would suggest that you be clear, complete, concise, and patient. The shorter your email the more likely he can reply immediately.
I also suggest you run an experiment and submit a link to a page somewhere, see if it has a comment box, log out, see if it's still there, log back in, delete it, then include the result of that in your email.