Leaving your e-mail in the newsgroups
These next few have basically the same answer ..... there are e-mail harvesting programs that work something like the search robots and spiders. What they do is search every IP address through every available page of information that is out there looking for someone@somewhere. It will then keep a list also keeping location of where it was found and any other information (if the location of the e-mail address supplies any additional information).
Newsgroups are only pages on the internet so any e-mail address there will be indexed. Webpages that do not encode the e-mail address will be indexed. Jokes that have been passed with the forwarded information can also be indexed if they are posted to a joke site.
Bottom line ...... when asking a question or replying in the newsgroups or post boards, come back to them for the answer, don't leave your REAL e-mail address.