If you talk to anyone who uses email, spam is something that is frequently on there mind. How often is it that you open your inbox checking for an email from your mom, and you end up with emails with subjective titles involving animals, and foreign objects.
There are ways to fight back against Spam, and one of the most popular is through the use of a spam filtering service. There is all different types of spam, and surprisingly not all of them involve email. Most spamming involves the advertising or otherwise promotion of a product, however this is not true in some cases.
Most common types of spamming include: Email spam, Link spam and search engine spam.
Email Spam is the simple act of sending out massive amounts of 'junk email' to anyone and everyone, in order to promote a product. Often times spamming has been exploited by more 'undergorund' industries such as the adult industry, but it would be unfair to say that other industries haven't used it as well.
Link Spam is a form of spamming or spamdexing that recently became publicized most often when targeting the increasingly popular weblogs. Weblogs is one of the biggest problems, however link spam also affects guestbooks, and online discussion boards. The purpose behind spamming these various places, is to display hyperlinks to a various page or product, which helps both with user exposure and search engine popularity.
Search engine spam is usually closely related with the above "link spam", as it is the process of creating countless numbers of pages, that populate search engines. Often times these pages will be full of garbage text and have no real value on there own. When a user visits them, they will either be re-directed to a completely different page, often times on another domain, or show prominent advertising.
Everyone can take their part in removing spam. The easiest way for a general user to not encourage spam, is not to use it. Spammers only spam, because it must be effective, otherwise they would find something better to do with their time. It is also recommended to get various levels of personal spam protection, which is often times included with anti-virus software. 3rd party solutions such as Hotmail, have very good spam detection, however often times spam will leak in, and in that case you can help hotmail out by notifying them of the occurence, so that they can better help protect you next time.