How does one contact the moderators to let them know that a comment is racist/sexist/whatever? I don't see any "flag" UI at the comment level, and I don't know who the mods are by name.
>>seldo+(OP)
If you click on the timestamp of a comment, you should see a 'flag' link. I don't recall, though it might be karma gated. You can also reach the mods via email to hn [at] ycombinator.com.