Request for Proposal or RFP - a form sent out by potential advertisers to websites or adnetworks that is used to elicit responses offering various rates, reach, and offers for the advertiser to select from. The "best" offer is usually the one the advertiser acts on and purchases advertising as a result of.

Frequency Cap - a term referring to a limit on the number of times a given ad will be shown to a given visitor from a website or collection of website. For example a website utilizing ads from an advertiser with a frequency cap of two would show their ad only two times to each visitor and no more. After the frequency cap is exhausted other ads woule have to be shown for other advertisers.

Reach - a term referring to the percentage of a website or networks traffic that a given ad reaches. For example an ad ran on a site of 1 million visitors that is seen by 100,000 of the visitors would have a reach of 10 percent of the sites traffic or 100,000 uniques. The term reach can also be used to refer to the web overall such that a website that reaches 10 million American visitors a month could be said to have a reach of 10% of all Americans if total americans online is estimated to be 100 million. Reach can also refer to the percentage of people online overall that a given website, network, or ad reaches.

Session - a term for a unique visitor per unit of time. A 12 hour unique session is a unique visitor in 12 hours, if the same visitor returns to a given site or network of sites more than once in 12 hours they would still only be counted once. Twelve hour sessions, 24 hour sessions, and once per browser session are common per session measurements used in online advertising.

Uncapped - a term usually referenced in popup or popunder advertising that means that the ad is not limited in the number of times it can be shown per visitor. To be uncapped is to have no frequency cap. An uncapped popup for example is a popup that will be launched on every page view a visitor has to a website. Each individual uncapped ad has less value to advertisers than ads with a frequency cap. Uncapped ads are also far more irritating to a site's visitors.

Traffic Leak - term for how merchants can set up their site such that one or more ads or links may result in zero commissions to affiliates that originally sent them traffic. In essence a traffic leak is a means to get out of paying affilaites for referring traffic to them through small leaks to nonpaying products or services. A merchant that pays 10% of sales to affiliates that send them traffic but pays 0% comission on gift certificates purchased at the site would be using the gift certificates as a traffic leak. Other methods of traffic leak include merchants who use affiliations with other sites to get out of paying thier affiliates for purchases from their site. If an affiliate sends traffic to a merchant site in the hopes they will buy shoes and the merchant site has links to other sites that sell hats or boots then the affiliate would get 0% often on people who buy hats or boots and such links would be traffic leaks.

IAB - acronym for the Interactive Advertising Bureau. The acronym used to stand for Internet Advertising Bureau but the name was changed to be more all encompasing. The IAB is an organization that promotes advertising online via research and by setting standards for advertising online. Many adnetworks and large publishers are members of the IAB.

Reversals - term for lead or sale based transactions generated by affiliate websites that are reversed due to invalid credit cards, or problems of various sorts such as returns or cancellations. For example with the Ebay affiliate program run at CJ one is paid upwards of $5 for every new person that signs up to bid there provided they bid within 30 days. After 30 days some people do not bid and their previous transactiosn are reversed for the affiliate.

Chargebacks - this is when consumers tell their credit card company that either they did not order something from an online merchant or that they were charged an inappropriate amount for the item or it was not as described. Since there are no signed reciepts like there are with in store credit card purchases in most instances the credit card companies will take a consumers word over that of a company in such matters. As a result a purchase online via credit card can result in a charge back or non payment to the merchant even if the item was sent and the information for the order has already been processed. Chargebacks can be due to merchant fraud though as well. Keep in mind that more credit card fraud online is done by consumers via chargebacks than by thieves who use stolen credit cards.

Two-Tier Commisions - these are affiliate programs that give their affiliates a percentage of the revenue generated by other affiliate sites recruited by the original affiliate. In essence an affiliate website gets comissions at the first tier for direct sales they refer and at the second tier for sales from websites they refer. Allposters is a famous two tier affiliate program for example.