Anything that is either overused, pleasurable or has become vaguely associated with the dopamine system is compared to cocaine.
In fact, here is a list of things claimed to be as addictive as the illegal nose powder in the popular press:
And here is a scientifically verified list of things genuinely addictive as cocaine:
In fact, the concept of ‘addictive as cocaine’ really makes very little sense. Even among drugs, cocaine has a unique chemical profile and social context that are the main things that determine its ‘addictiveness’.
Even if you wanted to make the vague analogy that rates of problematic use are similar you’d need to do a decent epidemiological study.
The classic research from the US reports that about 5% of users become cocaine dependent two years after starting the drug.
We are still waiting for a similar epidemiological study on the use of World of Warcraft or the consumption of cupcakes.
Link to cocaine entry on Wikipedia