Most of the better ISP's like Earthlink have a Spamblocker. Just to keep things nice and clean, I use their Suspect Email hopper for all of my forum mail as, IMHO, you can't be too careful. The suspect mail can be opened but it remains on the Earthlink server unless you are convinced it is OK and want to bring it into your in-basket.
Almost all of the folks here are on the level, but it only takes one that isn't, or even worse, has a corrupted email with a virus sitting as a Trojan Horse waiting to mess up your hard drive even though the sender's isn't.
The major thing is that unless you know the sender, don't open an email, and delete it. You might miss one that you shouldn't but I'm staying safe, not sorry