Randy Olson, a Ph.D. student in Michigan State University’s computer science program, has been trying to make sense of the vast, sprawling and sometimes lurid digital community that is Reddit, the self-proclaimed “front page of the Internet.”

His graphs show not only the most popular categories, or “subreddits,” on Reddit but also how the bulletin-board style forum has changed since it went live in 2005. Olson shows how Reddit has evolved from a place for users to share porn to a place for funny and weird content.

Subreddit Growth Over Time
A new study shows how Reddit has changed over the years. Randy Olson

Reddit added the /r/NSFW subreddit in 2006, and it immediately attracted interest. “Programming,” “science” and “politics” were also favorite topics, which perhaps aligns with most people’s stereotypes of techies from half a decade ago.

Things started changing in 2008. There was a notable increase in activity in the politics subreddit, as well as the creation of /r/pics, /r/funny, and /r/WTF, which all remain some of the most popular subreddits.

The introduction of the new “create your own subreddit feature” allowed Reddit users to sort content themselves, and that led to an explosion in new subreddits.

Increase in Subreddits
When Reddit introduced the "create your own subreddit" feature, the amount of categories exploded. Randy Olson

Today, Reddit is less focused on techies and politics and more on sharing fun and crazy stuff from around the Internet. Olson’s most recent data, from November 2012, shows that the top five subreddits are “funny,” “AskReddit,” “AdviceAnimals,” “pics” and “aww.” All remain popular today, so it’s unlikely that these have really changed much.

Most Popular Subreddits
Olson's data shows the most popular subreddits. Randy Olson

Olson makes several interesting observations about the Reddit community. For example, a subreddit dedicated to “Obama” was created in 2007, a year before the election.

You can read Olson’s entire study, which he published on his blog in March 2013, here.