1. Goto Settings: 
2. Download copy of your data 
3.Click on “Start my archive”: 
A link about how to backup also information from groups:
https://m.facebook.com/help/community/question/10152197183319968/?see_all=1
Facebook show you ads based on things they think you care about. Your preferences include information from your profile as well as actions you take on and off Facebook.
https://www.facebook.com/ads/preferences/edit/
What Wikipedia has to say about Graph Search?
Facebook Graph Search was a semantic search engine that was introduced by Facebook in March 2013. It was designed to give answers to user natural language queries rather than a list of links.[1] The Graph Search feature combined the big dataacquired from its over one billion users and external data into a search engine providing user-specific search results. In a presentation headed by Facebook CEO Mark Zuckerberg, it was announced that the Graph Search algorithm finds information from within a user’s network of friends. Additional results were provided by Microsoft‘s Bing search engine.[2] In July it was made available to all users using the U.S. English version of Facebook.[3] In December 2014, Facebook changed its search features, dropping partnership with Bing,[4] and eliminating most of the search patterns (from wikipedia).
From search bar of facebook you can do the following:
Search for Photos
My Photos
Photos I Like
Photos of my friends
Photos of my daughter
Photos of Michael Jackson
Search for Businesses
Italian restaurants at New York
Italian restaurants at beer sheva my friends have been to
pages liked by my friends
Search Pages
Pages liked by people who like Michael Jackson
Pages liked by Mark Zuckerberg
Search People
People who like Biking
People who like Biking and live in New York, New York
Friends who live in New York
https://developers.facebook.com/docs/graph-api
https://developers.facebook.com/