For reasonable time such problem can be solved with the help of the graph of the similar sites.
Idea such: manually we gather some sites which precisely suit us, somehow for everyone we find similar, we check them manually, suitable we add to set, we repeat procedure. If on each step accurately to select the sites, process will meet sooner or later, the graph of the similar sites will become isolated.
The similar sites can be looked for in Google with the help of key word of related, to take from Alexa and Similarweb.
Not to spend time for emptying of the suitable, but small sites, it is necessary to monitor how the total traffic on the sites from set changes. Usually it comes to plateau much earlier, than number of the sites in set.
Then the graph it is possible to use approximately to understand structure of subject. For example, the news sites happen about games:
This article is a translation of the original post at habrahabr.ru/post/264627/
If you have any questions regarding the material covered in the article above, please, contact the original author of the post.
If you have any complaints about this article or you want this article to be deleted, please, drop an email here: firstname.lastname@example.org.
We believe that the knowledge, which is available at the most popular Russian IT blog habrahabr.ru, should be accessed by everyone, even though it is poorly translated.
Shared knowledge makes the world better.