E-mail is widely regarded as the killer application in the whole history of communications. It's fast, easy and relatively cheap. If you ask around, you are bound to find out that most people's first experience with the Internet was sending out their first e-mail. Probe a little deeper and you'll probably find out that getting their first spam or unsolicited e-mail was quite memorable too.
Getting spam is like catching a cold. There are thousands of viruses that cause cold-like symptoms, and there's little chance that a person can build up defenses against all of them. Similarly, it is next to impossible to develop filters that block out all spam and spammers. There is one effective way of eradicating spam- stop using e-mail. However, this is not likely to happen in the near future, so we'll have to live with spam as how everyone has to live with a runny nose now and then.
The act of spamming basically involves flooding an e-mail users inbox with messages they would not have chosen to receive otherwise. Most spam is commercial advertising (often for dubious products), get-rich-quick schemes, getting a university degree or quasi-legal services. Spam lists are usually obtained from Usenet postings, stealing Internet mailing lists or searching the Web for e-mail addresses. It also costs very little for spammers to send out spam as it is usually sent out in bulk or paid for by the recipient or carriers.
As e-mail costs very little to send out, it is considered an ideal tool of advertising by companies. These e-mail marketing activities are described as permission-based because the recipients, or target audience of a particular e-mail marketing campaign have agreed to receive the e-mail concerned. The purpose of e-mail marketing is clear cut says one company; it's used for branding, marketing, and to generate sales. In terms of spam or unsolicited e-mails however, it aims to con some people into paying for something that they doesn't exist such as recent events of a few Malaysians who lost thousands of Ringgit in a Nigerian scam spam that asked millions of e-mail users to help free-up usurped royal coffers in 2002.

How did they get my e-mail address in the first place?

Getting spam upsets a lot of people. How were their e-mail addresses located? It becomes worse when spam comes regularly and in large numbers. It would good to be wary of e-mail's bearing gifts, although not all messages of this sort is unsolicited. Confused?
Well, remember when you signed up for that newsletter, and there were these little boxes with sentences that said 'Please un-tick if you don't want to receive any advertising e-mail'? No? Don't worry- you're not alone.
Most people do not read the terms and conditions and privacy policies properly when they sign up for something online, so technically, the unsolicited e-mails that someone receives isn't necessarily spam. To make sure that the e-mail that you receive is from an ethical marketing company, it will usually address you by name, as personalization is a key feature of such e-mails. If the e-mail addresses you by [email protected], it would be safe to assume that it's spam.
Regardless of method, there is only one way of preventing unwanted - not necessarily unsolicited e-mail. Read everything carefully! The most important thing is permission because permission based e-mail marketers have their reputation at stake.

Is there any law against spam?

At the moment, there is no specific law against spam although there are provisions under the Communications and Multimedia Act 1998 that relates to this. Section 211(1) of the Act states that "no content applications service provider, or other person using a content application service, shall provide content which is indecent, obscene, false, menacing, or offensive in character with intent to annoy, abuse, threaten or harass any person." Spam will be covered under the upcoming Communication and Multimedia Consumer's Forum General Consumer Code of Practice that is expected to be ready this year.

Filtering techniques

set a filter function in your e-mail account which you can check through regularly (eg: Hotmail's Junk Mail folder, Yahoo!'s Bulk Mail folder) or Block the e-mail completely

send complaints to your email provider about the spam or junk e-mail's that you are receiving as this might prompt them to take stern action against spammers

go through each spam/ unsolicited e-mail and unsubscribe from each one

use filter software (beware, as it may block out advertising that you have signed up for)

read all privacy policies and un-tick boxes that asks whether you want to receive advertising from that company- especially if it says that shares its e-mail database with other advertisers

Ranking Subject of unsolicited bulk mail Description
1 "Protect Your Computer Against Viruses for $9.95" Anti-virus spam was the most common this year
2 "Verification Department" Credit card scam has been prominent especially in recent months
3 "Refinancing? Get a Free Quote On Any Mortgage Loan Program" Mortgage spam holds its ground this year as a classic
4 "Printer Cartridges- Save Up To 80%- Free Shipping Offer" Printer cartridge spam, also a classic, is still one of the top spam
5 "Miniature Remote Control Car. Great Gift" A newer spam, an e-mail about toy cars for the holidays has hit e-mail accounts at full throttle in recent months
6 "$100 FREE, Please Play Now" Casino spam continued to stake out e-mail inboxes worldwide
7 "Online Auction Marketing Secrets" Online marketing scams bid heavily on e-mail users this year
8 "Important News Kuira" Septic system spam seeped rapidly through the Internet for quite some time in early 2002
9 "URGENT & CONFIDENTIAL" Nigerian scam spam asked millions of e-mail users to help free-up usurped royal coffers this year
10 "GET A FREE PASS TO THOUSANDS OF XXX SITES!" Pornographic e-mail slithered into inboxes, including those of children