lol sorry I don't know what MLP or IRC even are XD
MLP is short for My Little Pony, and probably references the most recent installment of it, My Little Pony: Friendship is Magic. It's found a surprisingly large following by young adult males, which can be seen, among other places, on a dedicated subforum of these forums
. Don't be deceived by the present lack of activity; when the next season starts, that subforum will probably become one of the most active ones here.
IRC is short for Internet Relay Chat. It's one of the earliest forms of Internet chat, but still sees quite a bit of use. Furtopia has an IRC server running; you can access the chat either through the web interface
or through an IRC client (connect to irc.furtopia.org on the *non*standard port 6007). As Avan alluded to, there are a number of Furtopians that use both the forums and the IRC, and some that exclusively or almost exclusively use the IRC (for example, Sasha has not posted outside of making an intro thread, and Shaun/silverfox usually only browses the forums if the IRC goes down).
...And yes, I am a fan of Homestuck. In response to the OP, though, I have a question. Did anyone wear the other forms of Dave's attire? Most notably, I see a lack of God Tier Dave, but there's a whole army of other Daves from his economic shenanigans that could have also been used. To get one of each together would have been *really* epic.