I'm currently scraping data such as "tweets, comments, likes" a website gets each day so I can graph them over time. One thing I am having a hard time scraping

I'm currently scraping data such as "tweets, comments, likes" a website gets each day so I can graph them over time. One thing I am having a hard time scraping backlinks to websites. Currently using bing but they are paid after like 5000 queries. I really wonder how other companies like seomoz do this daily against millions of websites.