• Consume bandwidth or space within the recipient's inbox
• Force people you know to waste time sifting through the messages and verifying accuracy
• Spread hype and, often, unnecessary fear and paranoia

There are two primary types of chain letters:

Hoaxes - Hoaxes attempt to trick or defraud users. A hoax often is malicious, instructing users to delete a file necessary to the operating system usually by claiming it is a virus. It might also be a scam that convinces users to send money or personal information.

Urban legends - Urban legends are designed to be redistributed throughout the web and usually warn users of a threat or claim, or to notify them of important or urgent information. Another common form are the emails messages that promise monetary rewards for forwarding the message or suggest that they are signing something that will be submitted to a particular group. Urban legends usually have no negative effect aside from wasted bandwidth and time

How can you tell if the email is a hoax or urban legend?
Most hoax messages appear normal, but be especially cautious if the message has any of the characteristics listed below. Not every hoax or urban legend has these attributes, and some legitimate messages may have some of these characteristics, but you should be cautious if you see them.

• Note whether the text you've received was actually written by the person who sent it. Did anyone sign their name to it? If not, be skeptical.
• Look for the telltale phrase, 'Forward this to everyone you know!' The more urgent the plea, the more suspect the message.
• Look for statements like 'This is NOT a hoax' or 'This is NOT an urban legend.' They typically mean the opposite of what they say.
• Watch for overly emphatic language, as well as frequent use of UPPERCASE LETTERS and multiple exclamation points!!!!!!!
• If the text seems aimed more at persuading than informing the reader, be suspicious. Like propagandists, hoaxers are more interested in pushing people's emotional buttons than communicating accurate information.
• If the message purports to impart extremely important information that you've never heard of before or read elsewhere in legitimate venues, be very suspicious.
• Read carefully and think critically about what the message says, looking for logical inconsistencies, violations of common sense and blatantly false claims.
• Look for subtle or not-so-subtle jokes — indications that the author is pulling your leg.
• Check for references to outside sources of information. Hoaxes don't typically cite verifiable evidence, nor link to Websites with corroborating information.
• Check to see if the message has been debunked by Websites that debunk urban legends and Internet hoaxes.
• Research any factual claims in the text to see if there is published evidence to support them. If you find none, odds are you've been the recipient of an email hoax

Before forwarding an email, asks yourself these questions:

• Does the email ask you to send it to a lot of other people?
• Does the email fail to provide confirmation sources?
• Is the language used overly emotive or highly technical?

These indicators do not offer conclusive evidence that the email is a hoax but they are certainly enough to warrant further investigation before you propagate a hoax and hit the "Forward" Button.