4chan is a popular image board that was founded in October of 2003 by user moot (Christopher Poole). The site was based off Japanese image board 2chan and originally focused mostly on anime, but has since branched out to include over fifty different boards with topics ranging from papercraft to pornography.
In relation to True Capitalist Radio
Initially, the members of the /b/ (random) and /v/ (video games) boards conducted raids on Ghost's show, then known as True Conservative Radio, yet they were generally unsuccessful in comparison to the more recent attempts. Following comments against the My Little Pony : Friendship is Magic fandom from Ghost (along with his absolute hatred of the bronies themselves), /co/ members who were fans of the show joined in as well (some of those raiders now frequent the newer board /mlp/). Other websites like Facepunch and 9gag (along with Ebaumsworld after DarkRazorZs videos became popular there) have also organized raids, 'combining forces' for the sake of 'lulz'.
Ghost dealt with 4channers as early as 2009, when a video posted of him getting very angry on his show surfaced there, leading to attempts to anger him even further, using methods such as by using memes and calling him names. This only molded Ghost's views on the internet even further and then developed his personality on the broadcast to suit a younger audience. He himself began to use memes such as Over 9000, Barrel Rolling and Lulz on his broadcast, to deter the trolls and entertain them at the same time, as part of his love-hate personality with the callers. The most famous series of raids occurred in June of 2011, which sent Ghost lots of unwanted attention, yet he eventually adapted to the sudden change through the introduction of Radio Graffiti, which he used to direct them away from the intellectual portions of his broadcast. Needless to say, 4chan still raids his entire show and the constant use of memes like the Sanic song and Fuck You Texas will always indicate their presence.
Ghost threads still pop up from time to time on the aforementioned boards above, yet some regard him as cancer now and that he should be ignored and forgotten. Some trolls post on 4chan posing as Ghost, and many use reaction images relating to him in responses (other large forums get their share of him as well, which is how the cancer rumor from December of 2011 began to spread). /mlp/ has shown a positive reaction overall to Ghost and his show and threads on him have reached as many as 150 replies.
Since the Return, there has been a /pol/ (politically incorrect) thread during every single True Capitalist Radio broadcast, usually several as they max out in posts. Bingo cards are often distributed and used by posters in these threads. After the end of the second hour, as Ghost goes into After Show segments, there is often a migration to TheBronyNetwork's live-streams and Tub Guy/Elfoxoloco's tinychat chatroom to listen to a relay of the post-show.
Since the start of Ghost's chatroom, many /pol/ users have noted the lack of activity in the threads posted during the show, with some shows having no thread posted for upwards of 30 minutes after the show starts, and recently having no threads at all since the move off BlogTalkRadio.
"4chan raids Ghost"
Many of the older True Capitalist Radio trolls came from raids conducted by members of /b/. These raids eventually led to a organized troll base and most listeners stuck along, listening to every show he broadcasted, some even becoming regular callers themselves. By mid-to-late 2011, Ghost threads were rarely posted as an attempt by the trolls to keep newbies from finding Ghost. However, a large amount of newfags still came to the show as a result of troll videos posted on Youtube; DarkRazorZs video '4chan Trolls Ghost - June 17th' has amassed half a million views, and is the most popular True Capitalist Radio video on the internet.
Ghost threads stopped altogether during his several-year hiatus, but got revivals whenever "Ghost" promised a return in one of his tweets. Since The Return, these threads are posted regularly again.