What is spam?
Spam is flooding the Internet with many copies of the same message, in an attempt to force
the message on people who would not otherwise choose to receive it. Most spam is commercial
advertising, often for dubious products, get-rich-quick schemes, or quasi-legal services.
Spam costs the sender very little to send -- most of the costs are paid for by the recipient
or the carriers rather than by the sender.
There are two main types of spam, and they have different effects on Internet users.
Cancellable Usenet spam is a single message sent to 20 or more Usenet newsgroups.
(Through long experience, Usenet users have found that any message posted to so many newsgroups
is often not relevant to most or all of them.) Usenet spam is aimed at "lurkers", people who read
newsgroups but rarely or never post and give their address away. Usenet spam robs users of the
utility of the newsgroups by overwhelming them with a barrage of advertising or other irrelevant posts.
Furthermore, Usenet spam subverts the ability of system administrators and owners to manage the topics
they accept on their systems.
Email spam targets individual users with direct mail messages. Email spam lists are often created
by scanning Usenet postings, stealing Internet mailing lists, or searching the Web for addresses.
Email spams typically cost users money out-of-pocket to receive. Many people - anyone with measured
phone service - read or receive their mail while the meter is running, so to speak. Spam costs them
additional money. On top of that, it costs money for ISPs and online services to transmit spam, and
these costs are transmitted directly to subscribers.
One particularly nasty variant of email spam is sending spam to mailing lists (public or private
email discussion forums.) Because many mailing lists limit activity to their subscribers, spammers
will use automated tools to subscribe to as many mailing lists as possible, so that they can grab
the lists of addresses, or use the mailing list as a direct target for their attacks.