For those of you interested in learning more, do sign-up for the Mining Massive DataSets[0] course on Coursera. It started last week and we covered the exact same concepts i.e. PageRank, Jaccard Similarity etc. talked about in this blogpost all taught by Stanford's esteemed faculty - Anand Rajaraman, Jure Leskovic & Jeff Ullman.
[0] - https://www.coursera.org/course/mmds