1. A popular canned meat product. Also, sending unwanted messages to a public forum, possibly a reference to the famous Spam sketch Spam Sketch by Monty Python. From KADOWKEV

2. Most spam comes through open SMTP relays. Spam is generally sent through the SMTP mail transfer protocol, though spammers are increasingly making use of web-based e-mail. A big source of spam comes from people who spider websites looking for web-pages that contain e-mail addresses. Since a lot of a web-sites will archive mailing lists and USENET groups, posting to a "private" list will often still expose your e-mail address. The SirCam worm of 2001 spidered the HTML files on the local web-browser cache to forward e-mail, creating a hugely effective manner for discovering new e-mail addresses. Spammers will usually spoof their e-mail address -- you can virtually never reply to the "sender" e-mail address. Netiquette: Use Bcc to send to multiple recipients rather than Cc: or To: fields in order to avoid exposing friends e-mail addresses to potential spammers. Firewalls don't block spam. The @Home cable modem ISP now regularly scans its customers for open USENET relays that spammers often hijack in order to forward spam on newsgroups. Some people are so emotionally against spam that they will will completely shun all access from networks known to be sources of spam. Websites will sometimes scan clients with SNMP or NetBIOS in order to discover their login name. Likewise, some websites sift HTTP fields for usernames (though virtually all web-browsers have disabled this feature). A Rumpelstiltskin attack is where a spammer sends e-mail to all possible names (a@example.com, b@example.com, c@example.com, ...) at a domain. This is similar to a brute-force attack. From Hacking-Lexicon

3. an SGML markup stream editor From whatis

4. vt.,vi.,n. [from "Monty Python's Flying Circus"] 1. To crash a program by overrunning a fixed-size buffer with excessively large input data. See also buffer overflow, overrun screw, smash the stack. 2. To cause a newsgroup to be flooded with irrelevant or inappropriate messages. You can spam a newsgroup with as little as one well- (or ill-) planned message (e.g. asking "What do you think of abortion?" on soc.women). This is often done with cross-posting (e.g. any message which is crossposted to alt.rush-limbaugh and alt.politics.homosexuality will almost inevitably spam both groups). This overlaps with troll behavior; the latter more specific term has become more common. 3. To send many identical or nearly-identical messages separately to a large number of Usenet newsgroups. This is more specifically called `ECP', Excessive Cross-Posting. This is one sure way to infuriate nearly everyone on the Net. See also velveeta and jello. 4. To bombard a newsgroup with multiple copies of a message. This is more specifically called `EMP', Excessive Multi-Posting. 5. To mass-mail unrequested identical or nearly-identical email messages, particularly those containing advertising. Especially used when the mail addresses have been culled from network traffic or databases without the consent of the recipients. Synonyms include UCE, UBE. 6. Any large, annoying, quantity of output. For instance, someone on IRC who walks away from their screen and comes back to find 200 lines of text might say "Oh no, spam". The later definitions have become much more prevalent as the Internet has opened up to non-techies, and to most people senses 3 4 and 5 are now primary. All three behaviors are considered abuse of the net, and are almost universally grounds for termination of the originator's email account or network connection. In these senses the term `spam' has gone mainstream, though without its original sense or folkloric freight - there is apparently a widespread myth among lusers that "spamming" is what happens when you dump cans of Spam into a revolving fan. Hormel, the makers of Spam, have published a surprisingly enlightened position statement on the Internet usage. From Jargon Dictionary