If you've been sent an email forward, especially the kind with some type of warning, it's worth it to try and find the email at snopes.com. For example, I just got an email forward warning about glade plugins burning down a house. When I searched snopes for "glade", I found this link:
http://www.snopes.com/toxins/glade.asp This email has been going around the internet for over a year and never been verified as a hoax or not. Things like this will happen all the time, usually from compeition (febreeze for example makes a spray can), or just someone playing a prank and seeing how many people it will get forwarded to. It's worth just browsing through the website too, lots of funny stories that are fake, and real: http://www.snopes.com/snopes.asp
Behind the scenes
The original RFC that covers email is [RFC821].
Email is sent over port 25. To test this out, find the name of your local SMTP server. We'll assume in this example that your mail server is mail.example.com and your email address is me@example.com, trying to send an email to your friend root@127.0.0.1:
$ telnet mail.example.com 25 Trying 10.0.0.1... Connected to mail.example.com. Escape character is '^]'. 220 mail.yashy.com NO UCE ESMTP EHLO example.com 250-mail.example.com 250-PIPELINING 250-SIZE 1024000 250-ETRN 250-STARTTLS 250 8BITMIME MAIL FROM: <me@example.com> 250 Ok RCPT TO: <root@127.0.0.1> 250 Ok DATA 354 End data with <CR><LF>.<CR><LF> This is a test message . 250 Ok: queued as 25CED619F
Signatures
Email signatures are usually prefixed with a --\n and shouldn't be any more then 4 lines long. For example:
-- Al Queda Minister of Conspiracy Bastard, Ontario, Canada +1(613)555-1212
