Spam is unsolicited bulk messages, especially advertising, sent through electronic messaging systems. It remains economically viable for spammers due to low costs and difficulties holding senders accountable. In 2011, the estimated volume of spam messages was around seven trillion, costing recipients and internet service providers in lost productivity and increased infrastructure needs. Legislation against spamming has occurred in many places to address the massive volumes of unwanted messages.

2.  Spam is the use of electronic
messaging systems to send unsolicited bulk
messages, especially advertising,
indiscriminately.

3.  Spamming remains economically viable
because advertisers have no operating
costs beyond the management of their
mailing lists, and it is difficult to hold
senders accountable for their mass
mailings.
 Because the barrier to entry is so low,
spammers are numerous, and the volume
of unsolicited mail has become very high.

4.  In the year 2011, the estimated figure
for spam messages is around seven
trillion.
 The costs, such as lost productivity and
fraud, are borne by the public and
by Internet service providers, which have
been forced to add extra capacity to
cope with the deluge.
 Spamming has been the subject of
legislation in many jurisdictions.

5.  Email
 Instant messaging
 Newsgroup and forum
 Mobile phone
 Social networking spam
 Social spam
 Online game messaging
 Spam targeting search engines (spamdexing)
 Blog, wiki, and guestbook

6.  Email spam, also known as junk
email or unsolicited bulk email (UBE),
is a subset of electronic
spam involving nearly identical
messages sent to numerous recipients
by email.
 Clicking on links in spam email may
send users to phishing web sites or
sites that are hosting malware.

7.  Spam email may also include malware
as scripts or other executable file
attachments.
 Definitions of spam usually include
the aspects that email is unsolicited
and sent in bulk. One subset of UBE is
UCE (unsolicited commercial email.