Besides blogging, I also enjoyed making notes for courses, books, seminars etc to serve my personal needs, and hopefully you regard them useful.
Machine LearningThe Machine Learning class 2012 at Coursera.
Project ManagementThe University of Washington Continuous Education program on 2013.
Distributed SystemStudy notes about the distributed system.
LeetCodeEverything about the interviewing: LeetCode, brain teaser, etc.
Misc reading notes.