Pay Per Call:

A model of paid advertising similar to PPC, except advertisers pay for every phone call that comes to them from a search ad, rather than for every click through to their website landing page for the ad.

A simple Google search of “pay per call tracking” comes up with about 355,000 results for this [...]

Visitor Segmentation:

Differentiating of users to site by categories such as age, sex, etc.

Being able to segment your visitors helps to target the ads best.  You can look at what pages different segments are spending the most time at and offer up the most relevant ads to that segment on that page.
Having ads more targeted to [...]

Index:

The database of web pages maintained by a search engine or directory.

Another common definition for index in terms of online would be the root directory of a website.  So, essentially, the base page of any site, search engine, or directory is the index.
Cryptic enough for ya? lol  This one is really self-explanatory with the definition…
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Glossary [...]

XML (eXtensible Markup Language):

Its primary purpose is to facilitate the sharing of structured data across different information systems.  It is used both to encode documents and to serialize data.

Related to HTML, XML aids webmasters in what they can do with their websites.  It’s another programming language out there.
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Glossary Definition From ABC’s of Online Marketing by [...]

Affiliate Fraud:

Bogus activity generated by an affiliate in an attempt to generate illegitimate, unearned revenue.

Commonly referred to as Black Hat activity, unfortunately there are lots of tactics that unethical affiliates can use to generate revenue.  Click fraud, redirects, adware, software programs, tool bars, etc.  There are many active affiliates out there that are working to [...]