Why do people (when they're posting their email address) type it in like frodo at baggins dot orc ? Are there spam trawler thingies that search the net for email addresses?

yes. infact, there are more than that. i get tons of spam from just having a mailto link with my name at the top of my forum. it doesnt even display my email in the open unless you point your mouse to the link, but inevitibly, i get mail because its there. mostly i get virii from people i dont know and people who i dont email or who dont email me, but the virii will pick up on that link in the browser, store it, and use it later to mail to me and to use as a spoofed 'from' address. at least, thats how i understand it.

I should have known, but now I do. Thanks

well, thats good to know!