If you're interested in what happened to the streamer a shorter over-view.
No popular streamers for league of legends were online due to it's ranked servers being down so he decided to stream. No ranked means people are interested in why it's down, people begin to watch his stream. (He's already a popular streamer). DERPTrolling contact PL (Phantoml0rd) via Twitter. NA servers for League of Legends get shut down, PL begins to play Quake Live, his server gets shut down on that too, PL decides to play DOTA 2, server gets shut down and then his viewers (Now around 40K) suggest he play Club Penguin. That then gets shut down before he even finishes making his account. PL decides to play on the OCE server for League of Legends and comments "If this gets taken down guys then these people really are doing it". Surely enough OCE server gets shut down. PL attempts to contact this group via his Vent server, that then gets DDoS'ed by other hackers, DERP set up their own vent, that then gets shut down by other trollers. DERP then proceed to attack EA, Origin and from what i've read a Korean news website. PL's stream hits 140K viewers (Breaking a record). People dox PL and publish his address, multiple pizza's are ordered to his house followed by 5 police cars and 15 officers who have been called about a "hostage situation" at the streamers house. PL's personal details, passwords etc, are breached and his stream is then hacked by a hacker.
TL;DR: Streamer tries to find out why these people are shutting down these games after being targeted by them, they get a lot of publicity from 140K viewers on his stream. Things blow out of proportion and the only reason supplied by DERP was "For the lulz".
http://www.twitch.tv/phantoml0rd/c/3472609
Video of the streamer explaining what happened (It's an hour long). Mid way through the video the police arrive at his house again. NOTE: This video may contain swearing.
EDIT: This means they attacked EA, Origin, Disney (Club penguin owners), Riot, Blizzard and Valve. A common trend between these companies is micro-transactions. Rumours began circulating once the ordeal ended that they were targeting money hungry companies.