Brony is a term for an adult fan of My Little Pony: Friendship is Magic outside of the show's target demographic. The name originated on the /b/ board of 4chan: a combination of /b/ and ponies. Bronies of all different shapes and sizes exist on the internet, and frequently hang out in Synchtube, 4chan's /co/ and /b/ boards, Ponychan, FiMchan, and various other brony websites.
Story time, fillies and gentlecolts! In October of 2010, there was unrest on /co/. A brand new My Little Pony cartoon was about to air, and a thread popped up discussing it and other Hasbro property reboots. Five /co/mrades decided to watch the first episode for laughs when it aired. They returned to /co/ with an interesting tale to tell--the show didn't suck as they had expected. It was actually really good. These five got tripcodes and hung around /co/ for a while, discussing the show. They were:
Flutter!Shy.frIUO2, age 16
Apple!jack, age 22
Pinkie!pie, age 20
Rainbow!Dash, age 23
And Big McIn!toshdAyGxE, age 14,
Of these original five, only Big McIntosh is still known to be around. His more known name is Arctic Tempest.
Anyway, /co/'s very first MLP general was so full of curious /co/mrades, it reached bump limit and image limit, much to the surprise of, well, everypony. So another thread was made. That thread autosaged as well. YouTube user Pensivepony (then Pensivepine) uploaded the first episode to YouTube. /co/-goers watched it, and loved it. More bronies were born. As more episodes came, so did more bronies. Some neighsayers began making fun of the bronies, but most bronies really didn't care. It was also around that time that the first writefriends and drawfriends also began appearing. MLP generals became a constant sight on /co/--if there wasn't one on the front page, that simply meant the old one had only just reached autosage or image limit. Some animosity towards the bronies was brewing, but as long as they had a place to discuss the show, they didn't care.
In a private chat between the original 5 bronies in December, they decided that they should see if they could spread the pony love to other parts of 4chan -- namely, /b/. So, they did. They started a simple pony thread on /b/. And, much to everypony's surprise, it caught on. /b/ suddenly exploded with pony threads. At one point, you con the front page. More and more bronies were born in the /b/ pony threads. The /b/ pony threads took on a copypasta format, that went a little something like this:
THIS IS THE OFFICIAL PONY THREAD; IF YOU SEE ANOTHER, DIRECT THEM HERE!? If there are multiple threads, the older thread should ideally become the 'go to' thread, unless another thread is more active.) Everypony equal. Everypony Loved. You don’t have to have a tripcode to be a brony, it’s just for fun. Due to complaints, the links have been removed from the OP copypasta, but a brony will always be ready to help anypony who asks!
Love, Tolerance, Friendship, and Kindness are the most important things a /b/rony can have, let’s spread some joy and post some ponies!
Ponies were becoming the biggest thing on the internet and were thenumber one trending topic on Know Your Meme. It was around this time that the two pony-related chans were created: FiMchan, established by bronies from /co/ (also known as /co/lts), and Ponychan, established by /b/ronies. Equestria Daily was also created around this time. At that point, the hatred towards bronies was really festering. Spammers attacked the /co/ and /b/ threads daily, but most bronies, as previously stated, didn't care as long as they could discuss their ponies. However, a while after that, the unthinkable happened. On February 26th, 2011, a rogue /b/ mod placed an autoban filter on the word "pony." He then went into the active pony thread and banned everyone in the thread for a month--including some of the spammers. Bans started happening on /co/ too.
It was around this time that Ponychan started getting lots of users, as many /b/ronies wanted a place to go, but didn't use FiMchan due to some tension between the /co/ portion of the fanbase and the /b/ portion. Soon, ponies became okay on 4chan again, leading to more bronies being born. Today, bronies are undeniably a huge thing on the internet. MLP is still at the top of the trending topics list of Know Your Meme, and is the most viewed page. Equestria Daily has had over 20 million views. /co/ threads still reach autosage and image limit every time, and there is now an archive of them here. /b/ still has pony threads many times a day. Ponychan gets a ton of traffic, mostly on its most popular board, /oat/. Bronies from SomethingAwful have also created a pony-related form, known as Ponygoons. Ponies are rapidly taking over the internet. Resistance is futile; you will be assimilated into the herd.