The wikipedia article doesn't mention how long this has practice existed, but I know this goes back to at least the late 90s. Circa '98 IIRC, there was a modul

The wikipedia article doesn't mention how long this has practice existed, but I know this goes back to at least the late 90s. Circa '98 IIRC, there was a module available for a webserver I worked with which generated a page with number of bogus email addresses per page, and a number of random urls per paged that when followed generated yet another page of bogus email addresses and links. You hid the link somewhere on a legitimate page, added the base path as an exclude in robots.txt, and any mail harvesting spam-bots would get sucked in. The idea may well have been around longer still.