A scraper site is a website that copies all of its content from other websites using web scraping. No part of a scraper site is original. A search engine is not a scraper site: sites such as Yahoo and Google gather content from other websites and index it so that the index can be searched with keywords. Search engines then display snippets of the original site content in response to your search.

In the last few years, and due to the advent of the Google Adsense web advertising program, scraper sites have proliferated at an amazing rate for spamming search engines. Open content sites such as Wikipedia are a common source of material for scraper sites.

Made for AdSense

Some scraper sites are created for monetizing the site using advertising programs such as Google AdSense. In such case, they are called Made for AdSense sites or MFA. This is also a derogatory term used to refer to websites that have no redeeming value except to get web visitors to the website for the sole purpose of clicking on advertisements.

Made for AdSense sites are considered sites that are spamming search engines and diluting the search results by providing surfers with less-than-satisfactory search results. The scraped content is considered redundant to that which would be shown by the search engine under normal conditions had no MFA website been found in the listings.

These types of websites are being eliminated in various search engines and sometimes show up as supplemental results instead of being displayed in the initial search results.

Google offers a domain parking service tailored for this kind of site. These supposed parked domains often run Google Adwords to attract more visitors to their site in the hopes that they will click on Adsense ads and generate a greater return than the original cost of the Adwords click. For many this has been a successful business plan, and one that Google has failed to combat.

Legality

Scraper sites may violate copyright law. Even taking content from an open content site can be a copyright violation, if done in a way which does not respect the license. For instance, the GNU Free Documentation License (GFDL) and Creative Commons ShareAlike (CC-BY-SA) licenses require that a republisher inform readers of the license conditions, and give credit to the original author.

Techniques

Many scrapers will pull snippets and text from websites that rank high for keywords they have targeted. This way they hope to rank highly in the SERPs (Search Engine Results Pages). RSS feeds are vulnerable to scrapers.

Some scraper sites consist of advertisements and paragraphs of words randomly selected from a dictionary. Often a visitor will click on a pay-per-click advertisement because it is the only comprehensible text on the page. Operators of these scraper sites gain financially from these clicks. Ad networks such as Google AdSense claims to be constantly working to remove these sites from their programs although there is an active polemic about this, since these networks benefit directly from the clicks generated at these kind of sites. From the advertiser's point of view, the networks do not seem to be making enough effort to stop this problem.

Scrapers tend to be associated with link farms and are sometimes perceived as the same thing, when multiple scrapers link to the same target site. A frequent target victim site might be accused of link-farm participation, due to the artificial pattern of incoming links to a victim website, linked from multiple scraper sites.