Spam is the use of the electronic communication system (not only emails but also messages, comments, spam on social networks and other forms of communication) to send unsolicited messages and communications. One of the most widespread and well-known forms of spam is email spam – the most common are cases where fraudulent emails offer various types of medical products, job offers, easy ways to get large amounts of money, etc.

E-mail spam

E-mail spam, also known as junk e-mail, is a form of spam where the same or nearly the same message is sent to many recipients. Email spam goes unsolicited, is not a reply to anything and may contain advertising messages, fraudulent information and potentially dangerous links.

Spam in the form of emails is constantly increasing and more than 80 percent of email spam is handled by so-called botnets. A botnet is a network of virus-infected computers. Spammers retrieve emails from websites, chat rooms, customer lists, individual users' address books and other places.

It is estimated that in the first half of 2010, spam accounted for up to 92 percent of all emails sent. And as much as 81 percent of all spam consists of ads for drugs, most commonly Viagra. Other spam offers include various replicas (e.g. of watches), weight loss products and guides, casinos and other fraudulent offers.

Instant Messaging spam

In addition to email, instant messaging (IM) systems are often affected by spam – these include ICQ, AIM, Yahoo! Messenger, Windows Live Messenger, Facebook chat, etc.

Some IM providers have publicly traceable databases of users, including their age, gender, residence and other information, making them an interesting target for spammers. The IM program then sends users similar messages to email spam – offers of cheap drugs and products, opportunities to get large sums of money quickly, fraudulent job offers, etc.

Spam on discussion forums

Discussion forums, wiki systems, guest books and blogs are frequent targets of so-called comment spam – spammers register accounts on individual sites, which then post advertising or other inflammatory messages to the discussion, often with links to other sites. Again, this is the traditional combination of tips on how to lose weight, pornography, gambling, drug offers, etc.

Spam comments are often just links, or links with little text. Automated spam filters have recognised the frequent publication of comments with only links to external sites, so it is common to see spam comments that contain more text or have links to scam or advertising sites in the so-called signature of the post.

Spam blogs

Spam blogs, or blogs created solely for spamming, are automatically created blogs with a large number of links that do not necessarily annoy the user, but serve to fraudulently increase the pagerank of other sites, which can thus get higher positions in search engines.

This can often result in thousands of blogs on the same topic with similar addresses, a large database of keywords and phrases, and a large number of links.

Spam in online games

Online games (MMOs, often specifically the MMORPG genre) allow players to communicate with each other using both voice and text. Communication in online games can be between two players, a group of players, or between an entire region or server.

Thus, spammers often set up virtual characters in online games that are not used to play the game, but only to send messages to individual players and to send public messages. Among the classic advertising messages about viagra and money, the sale of the virtual currency of the game in question for real money is often offered. Spamming about the sale of virtual in-game items or other in-game services is also a popular form.