Story highlights With 172 million active monthly users and growing, politicians have taken notice of Reddit's influence

The themes of Sanders' campaign -- free college, jobs and getting big money out of politics -- speak to Reddit's demographic: Young people.

New York (CNN) How is Bernie Sanders amassing such large crowds? One of his tricks might be Reddit.

With Bernie Sanders about to come on in Madison, the arena is more or less full. pic.twitter.com/TXMV7Agtfz — Dan Merica (@danmericaCNN) July 2, 2015

For those that don't know, Reddit is a popular website community and social platform where registered users (which can really be anyone on the Internet) post and share links, comments and questions. Posts are then ranked up or down by the site's users, which helps measure the popularity of particular post. There are also "subreddits" which are communities for more focused and targeted conversation. For example, in the "news" subreddit, users only discuss and share news.

The site, which is known for its sparse layout, relies on the conversation and sharing if its users. For a long time, outsiders thought the site was intended for more niche audiences within the Internet community.

But times have changed, and with 172 million active monthly users and growing, politicians have taken notice. In 2012, President Obama participated in his first Reddit AMA, short for "Ask Me Anything," where users were allowed to ask the President anything. For example: "What's the recipe for the White House's beer?"

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Other politicians followed suit, namely Sanders. Unlike his contenders in the 2016 race, Sanders holds a unique and grassroots following on the site, more than any one else in the 2016 race. According to Reddit spokeswoman Ashley Dawson, Sanders is among the most active on the site, conducting his own Reddit AMA to 8,593,027 subscribers shortly after announcing his run for the presidency, engaging directly with users about his candidacy.

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