Beeing paid to search is one of the many kinds of methods to earn money on the intenet doing something pre-defined in websites.

There is a important concept that you need to know in PTR and PTS business: the search and the valid search.
Usually most of advertisements in PTR sites are links to search engine portals.
The owner of the PTR site earn money (used to pay us) if we do valid searches in the search portals. If we don't do the searchs the owner of the PTR site doesn't earn money and at long term he loses money and his site is in risk (and our earnings).
In your account you can choose if you want receive search's advertisements. If you choose it you should do the searches because if you don't do it you are causing losses to the site and to the other users. If you don't want do searches don't check that option in your profile page.

In a search portal there is a search box and several keywords.
When we search anything using the search box or we click in a keyword a search is done.
However the owner earns money only when the search is valid. A search is valid when after doing the search we click in one of the links resulted from the search and wait to full download of the advertiser webpage.