For most of people, its hard to define differene between hobby and addiction. But its actually similar to know about other hobbies and its addiction.
Usually, addiction relate to something you do without any goal. In the sence of games, most people love to play games. They always find it more excited as developers serve new materials quickly. Addict only love to play those game. They have no targets and mostly plays it all day and night.
On the other hand, pros know more then just playing games. Similar to other fields, game industry is very huge that most of people dont know that they do yearly game show like oscar award where leading development firms come together to reperesent their best effort (E3 show). For people having gaming as hobby, they know things happen from one get an idea of making new game till launching that game and its downloadable contents. They know about global companies, software and technology used in developing game, current industry scenario and most important what comes next.
All in all, for every hobby, you can define what addiction is and what actual hobby looks like.
I think it’s sometimes best to illustrate this with a story.
So, I used to play WoW. A lot. Probably too much, truth be told. For a really long time I played it because it was fun, and I enjoyed playing with people I knew. However, one by one they started disappearing due to real life. Then one day I realized, I never played with them anymore and was just grinding dailies or random pick-up raids and instances. It wasn’t fun at all and I was paying for it to boot- so I quit too.
A friend of a friend of mine was pretty into WoW too. However, he was… a bit more so. You see, there was one little situation where his wife went into labor. He was at home, about to head to the hospital, but decided to check his mail. One thing led to another, and he ended up missing the delivery. Needless to say, this did not go over too well with the Mrs.
I’d say that I did it as more than just a hobby, it was much more time than I’ve spent with any other hobby for sure (e.g. scale modeling, which I also enjoy to this day). However, it wasn’t addiction- when it wasn’t fun anymore, I put it down.
The other guy… that’s addiction. He couldn’t put it down even when obviously much more important things were taking place. Addicts are incapable of putting their addiction aside and need to undergo therapy to stop it. That also goes for things like smoking, alcohol, other recreational drugs, gambling, etc.