A Brief History of Cybercrime and Cyberwarfare - The Technical and Social History of Software Engineering - page 411

Ordinary spam ads are legal in the United States under the CAN-SPAM Act of
2003 and are probably protected as a form of free speech under the Constitution.
Spam that contains viruses or can cause harm to computers or consumers is not
legal. The European Union, on the other hand, does have explicit laws against
spam, although that is not the same as stopping it.
In every country, spam usually violates the terms of service of the ISP and can
be blocked or deleted if detected. ISP owners can also attempt to collect dam-
ages from spam originators through lawsuits, although these are not easy cases to
pursue. The damages are based on misappropriation of bandwidth and server re-
sources, which have financial costs that can be quantified in court.
The fact that sending spam is now the largest user of internet resources has
spawned two growing subindustries. The first is that of the spam creators who
sell their services to clients who want to issue bulk ads. The second and smaller
subindustry consists of the companies that design and market antispam tools for
blocking spam from emails and instant message sources. The first industry of
spam creation seems to be more profitable than the second industry of spam avoid-
ance.
The actual technology of spam is complex and diverse and outside the scope of
this topic. There are more than a dozen variations for creating and sending spam
messages.
The first known spam broadcast was perhaps an ad for DEC computers sent
to 600 ARPANET users in 1978. In today's world, Microsoft's security unit re-
ports that spam makes up about 97% of current email traffic. A remark by Steve
Ballmer of Microsoft reported that Bill Gates, the Microsoft founder, is sent about
four million emails per year, with the vast majority being spam.
Because spam apparently originated in the United States, it is interesting that
it remains the number one country for spam origination. The European Union is
number two and China is number three.
In today's world, email without effective spam blocking is almost unusable.
(When I used older email servers that lacked effective spam blocking, about 200
spam messages arrived per day.) With modern email services, such as Gmail, that
include spam blocking, only one or two spam messages seem to slip through.
Spam is no longer restricted to computers but is also present on tablets and
smartphones. In fact, robo calling , or using software to make recorded calls to tar-
geted lists of phone numbers, is a very annoying form of spam for landlines.