Get Paid to Read (PTR): the most basic form of GPT, where users sign up to receive email advertisements. Upon reading the emails, users click on a link provided which opens the advertiser's web site for up to 60 seconds. Circa 2006, users are paid between 0.01 and 3 cents per email read. All amounts and times are specific to the website and advertisement. In its early years (circa 2000-2003), many companies paid members up to 10 cents for clicking these advertisements; this has decreased as online advertising grew and the market became saturated.
Get Paid to Click (PTC): a variant of PTR, where the user simply clicks on web banners or textual advertisements on the website itself. The PTC program does not need an email server for this, but as users need not read the email first, PTCs usually pay much less than 1 cent per click.
Get Paid to Promote (PTP): a website provides web pages for users to promote. Whenever another person views this web page, the user is awarded a certain amount of credits. After earning enough credits, the user can redeem them for money, generally at a rate of 50 cents to $1 per 1000 views. PTP pages are often promoted through PTC ads, PTR emails or PTS sites.
Get Paid to Surf (PTS): users access a website which rotates the page viewed in the web browser window. Users are paid very low amounts (fractions of a cent) per page viewed, because in many cases they need not actually view the rotated adverts or even be at the computer. Traffic exchanges and autosurfs are variations on this concept.
Get Paid to Sign Up (PTSU, also PTS): Users are paid around 5 to 50 cents for signing up to programs such as other GPT sites, forums or HYIPs. Users of those other programs pay people to sign up as their referral, as they hope to earn more than they spent through receiving commissions.
Get paid to complete offers: Users are paid several cents up to $50 to complete offers, such as signing up for a credit card, subscribing to a magazine or mail video rental service, or joining a mailing list. Websites which provide such offers normally also have a referral system, and may be paid by large companies to provide them.
Get Paid to take Online Surveys: Users that fit certain demographics are paid to complete surveys hosted by online market research firms. Payments for surveys can vary quite drastically. A user may be paid a few cents for a three question poll, or hundreds of dollars for sampling a product and participating in a market research discussion group regarding it
Get paid to post (on forums): Forum members are paid for posting. Usually, they are paid to post in some part of forums, excepting Chit-chat and that sort of casual talk. Rules are different on different forums, but generally opening new topics are better paid than replying posts.
HYIP, or High Yield Investment Program, is a type of investment scheme normally offered via the Internet. HYIPs accept deposits as low as $1 while promising astoundingly high returns.
Scams They have their own section here