It's not just Facebook... applications know you, too!

This blog, and others, focuses on Facebook settings and how to make them work for you. But there are thousands of third-party Facebook applications out there (games, quizzes, photo sharing, review sites, maps... the list goes on) that make money from you.

They'll do so mainly either via affiliate links or straight ad revenue. What does this mean? Here are some real-life examples.

Affiliate revenue: Say you've installed an application that allows you to list the books you've read. If a visitor clicks on the book title, they'll be taken to an online bookstore where they can buy a copy. If the visitor goes through with the sale, the application developer, who has set up a deal with the bookstore, will get a cut.

Ad revenue: You might see Google ads at the end of a game. Click on an ad and the app maker will get a cut. Many websites, including this one, display similar ads.

Sometimes an application has no ad links and is a brand awareness exercise. The agency will want to convince their clients that the application is helping the brand name get across.

To measure the effectiveness of these campaigns, application developers need to be able to see demographic information about the people who use their tools. They can use analysis tools from companies like Refresh Analytics, who allow developers to get stats about people who add their programs. Refresh Analytics' tool is described thusly:

The tool can be easily integrated into any Facebook app. It tracks users across 13 demographic and six interest categories: geography, gender, age, marital status, music, books, etc. The info is collected in aggregate to protect user privacy and respect Facebook rules. A daily snapshot of 1,000 users is provided, and historical reports can be generated for the past month, six months or two years.

So, although personal information about you is never revealed, if you have included information about where you're from, your age, marital status and interests, all this information can, and does, get pulled out and it's able to be broken down by app makers so they know, say, the average age of the person who plays their games.

That's why I've not listed any interests or even my gender in my profile. I don't need the advertisers to know all this information if I don't have to reveal it.