Today I added some commands that you can use in the heylisten chat.

/help - prints some notes on how to use commands right in the chat
/me - works the same as the IRC /me command

/adduploads <platform> <channel> <number of videos 1-20> - will add the specified number of newest songs from the specified channel from the specified platform.
So for example /add youtube mrsuicidesheep 10 will add ten sweet songs from MrSuicideSheep to the playlist.
/addplaylist <playlistID> <number of videos 1-20> - will add the specified number of songs from a given youtube playlist.
/addplaylist PLDfKAXSi6kUba6EDLtCojcKg45Uwp39Bh 10 will add ten songs from this playlist.
I also added a shortened versions of the last two commands so if you don't feel like typing too much use /addup and /addpl.

Right now the add command only supports YouTube, but I'll be adding support for SoundCloud and Vimeo very soon. As time goes on I will be adding more commands so stay tuned for that. I'm also looking into adding emoji to the chat since someone already requested that.