Right now, as a service to the Hackernews community, I wouldn't consider charging anything. If this really takes off (unlikely) then I'd consider setting up a service where people can pay each other through the site, with my holding the money in escrow until both parties agree the transfer has gone through. In that case I'd have to figure out how much that would be worth.

The search function is a mysql fulltext. Obvious drawbacks to searching for words inside of words, so I added a "tags" parameter. Obviously this is not a great solution, but I don't know of too many better options. :/