traffic-exchanges-explained

Well, this is how wikipedia describes a Splash Page:
On the Internet, a splash screen or splash page is a page of a web site that is a sort of pre-home page front page. Designers may use splash pages:

* to restrict access to content such as pornography, alcohol advertising or sales, or gambling (as is required by law in many countries, including the United States and Canada);
* to direct users to the appropriate website for their country or language;
* to direct users to a low-bandwidth site or one more accessible to disabled users;
* as an aesthetic compliment to the main page;
* as an additional form of advertising.

Since splash screens often increase the distance to the desired content and may take a long time to load, they are not universally liked by users. Web splash screens are especially inconvenient for users with slow internet connections as the first page may take longer to load or if the user has turned off rich content (such as images, Flash or Shockwave), the splash page may not load at all. Splash pages created in Flash (and the associated main pages) often cannot be accessed by search engines or handled by text readers for the blind.

Basically in the context of Traffic Exchanges it is the last option we are interested in:

"* as an additional form of advertising.
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You can find a lot more information on the topic here at wikipedia