Professional SEO | Internet Marketing

Pay per click campaigns can be categorized into two major categories: sponsored match (or keyword) and content match. Sponsored match campaigns involve the display of ads on search engine results pages, whereas content match campaigns involve the display of ads on publisher websites, newsletters, and e-mails.

Keyword pay per click advertisers bid on search terms — keywords consisting of words or phrases, and possibly product model numbers

the following are notable PPC keyword search engines:

• Ask.com
• Baidu
• Google AdWords
• LookSmart
• Microsoft adCenter
• MIVA
• Yahoo! Search Marketing
• Yandex

Product engines (a.k.a. product comparison engines or price comparison engines) are search engines for products, and let advertisers provide "feeds" of their product databases.

The following are notable PPC product engines:

• NexTag
• PriceGrabber
• Shopping.com
• Shopzilla

Service engines let advertisers provide feeds of their service databases. When a user searches for a service, links to advertisers are displayed for that particular service

The following are notable PPC service engines:

• NexTag
• SideStep
• TripAdvisor

Pay per call is a business model for ad listings in search engines and directories that allows publishers to charge local advertisers on a per-call basis for each sales lead (i.e., call) the publishers generate.

Pay per delivery (PPD)

Pay per delivery is a variation on pay per click used in e-mail marketing. Email marketing campaigns are charged only on the basis of e-mails that are delivered successfully.

Pay per action (PPA)

Pay per action is a variation on pay per click adopted by many search engines. An advertiser pays a specified amount upon successful completion of some action

[via wikipedia]