An issue most privacy advocates don't think much about is that there are only three high-end search engines in the world who sport their own index. Google, Bing, and Yandex are about the only authoritative general-purpose search engines capable of giving usable results to common queries. Most other alternatives (such as DuckDuckGo or Startpage) just act as front ends to these. Smaller alternative search engines who have their own web crawlers and indexes just don't have big enough databases to give good results, or are too specialized (see the "Why Not an Open Source Big Index" box).

The three big search engines, therefore, comfortably dominate the market. This is a problem for a number of reasons. First of all, if you use one of these engines directly (i.e., you perform Google searches from your computer), the engine gets to know what you search and, eventually, will produce an accurate profile about your interests. Because mainstream engines get to see the queries of most Internet citizens, they can make a profile of nearly everyone. Using a front end such as Startpage alleviates the problem: Google does not get to correlate your searches with your identity, because the alternative front end acts as an anonymizing proxy of sorts, but you still have to trust that the alternative front end is playing fair and not profiling you itself.

Secondly, whether you use a big search engine directly or not, at the end of the day you only get the results that the big indexes want you to find. If you use DuckDuckGo, you are indirectly getting Bing results. If there is an article Microsoft does not want you to read, the article won't feature high in the list of results, if at all. Because most netizens only use big search engines, these big search engines get to decide what most people find.

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