@makingaplan, all of these responses are basically correct.
1) in most countries and jurisdictions, it is illegal for you directly provide information or support to someone attempting suicide. Here's a starting point for you.
http://en.wikipedia.org/wiki/Assisted_suicide
2) providing sources in a public thread or post can qualify for #1, and is against SaSu rules. This is a quick way to get banned. However, what happens in a private message is not monitored unless specifically reported to us.
3) chances of successful criminal prosecution would be very small, as they would need to track you down and build a case using data from anonymous website. But if you aren't careful, it could be done. There would be other factors, such as is SN legal in your jurisdiction, and freedom of speech rights that would come into play.
tl;dr; be careful with what you post and who you share information with.