What is Spam?

'Spam' is the blanket name given to a variety of different practices, the common feature of which is that they all involve the use of electronic messaging systems to indiscriminately send out bulk messages. Perhaps the most widely recognised form of spam is email spam, but there are a number of variants including blog and forum comment spam, instant messaging spam and social networking spam.
Some estimates have placed the number of spam messages sent during 2011 at somewhere around 7 trillion messages. Although it is difficult to calculate the total cost of these unethical practices, it is clear that internet service providers and the general public suffer most from the propagation of these messages as a result of wasted time and increased pressure on internet services. Unfortunately for the internet user, it is difficult to hold either businesses or individuals to account for spamming.
According to some figures, as much as 80-90% of all email worldwide constitutes spam. Fortunately for the end user, the vast majority of this is filtered out before it ever reaches the inbox of a potential recipient, although this has reduced public awareness of the scale of the problem.
Purposes of Spam

There are a number of different purposes for spam messages and these tend to dictate the medium through which they are transmitted. For example, a large quantity of email spam comes from businesses that are trying to publicise their products and services in the hope of making sales. In this context, email spam can be considered a (usually) less targeted and more modern equivalent of traditional junk mailing. Often, although not always, businesses that engage in spam are selling ethically questionable products - businesses with hard-earned good reputations will often steer clear of unsolicited email messaging because it can reflect badly on them.
Spam in the form of forum and blog comments often serves a different purpose. Although this type of spam can also include information about products and services, it most often contains links.
This type of spam came about largely as the result of search engines counting backlinks to determine the relevance and value of a given link destination. Spammers quickly realised that by sending out blog and forum comments containing links en masse (some blogs and forums are set to auto-approve comments before they are moderated) they could boost the search engine rankings of a given web page and thus drive traffic in that direction. This can generate revenue in a number of ways, the most common of which being through advertising banners.
For this reason, there are also a number of unethical search engine optimisation companies that choose to promote the web sites of their clients using spam. It should go without saying that engaging with such agencies is a poor business decision. Not only can this put the reputation of a company at risk, it is unlikely to provide value for money in the long term. Search engines are increasingly capable of detecting and punishing web sites that are promoted through spam.