MongoDB Arrays for Social Likes and Follows
In social sites, you generally want to like something (comment, post, page, etc), or be a friend with someone. Now, MongoDB has arrays, which can be indexed are perfect for this we found out.
While most of these scenarios will work just fine, the one that can get a bit more complicated is handling highly concurrent likes/counters.
Original title and link: MongoDB Arrays for Social Likes and Follows (NoSQL databases © myNoSQL)
via: http://www.w3matter.com/journal/2010/9/30/mongodb-arrays-for-social-likes-and-follows.html
