My strategy is to use a catch-all and filters (with Google Apps). I have my catch-all for the domain go to an address like spam@<mydomain>, and then within that

My strategy is to use a catch-all and filters (with Google Apps). I have my catch-all for the domain go to an address like spam@<mydomain>, and then within that account have a filter set up such that all email with a destination that includes my code gets forwarded to my real address. For example, I sign up to HN with the email address hn.rfg@<mydomain>. This gets forwarded to my real address because it's got the rfg string in it. If I start to get spam on that account, I can add a filter for hn.rfg on either my real or spam@<domain> account, depending on which is more convenient, and I know where it came from. Blanket spam to <mydomain> rarely comes through to my email, since the to is unlikely to include the rfg string, and will probably get picked up by the spam filter on the spam@<mydomain> account. Backscatter spam with faked from headers rarely gets to my real account, since the faked address is unlikely to include the rfg string.