Someone sent out a link or something and it led to a bunch of booster comments. That's not allowed on HN, so I killed the comments and emailed the founders asking them to make it stop.
We make a distinction between innocent mistakes (which are usually obvious) and repeat offenses (where people usually try to cover their tracks). The former isn't a big deal, the latter we ban accounts for.
The guidelines say not to do it: https://news.ycombinator.com/newsguidelines.html, the FAQ says not to do it: https://news.ycombinator.com/newsfaq.html, and the Launch HN advice we give to YC startups says to "make sure" (in bold!) not to do it: https://news.ycombinator.com/yli.html. But people who aren't familiar with HN's conventions still end up doing it sometimes.
We make a distinction between innocent mistakes (which are usually obvious) and repeat offenses (where people usually try to cover their tracks). The former isn't a big deal, the latter we ban accounts for.