"Casual gamers are those who do not care about gaming, and play only "casually",  a few times, for example when they run into them at a friends' house, or in a web browser.  "

-That is the most frequent definition of "casual gamer". But let's look into the statistics:

1)

The Wii is usually considered to be more casual than the other two this-gen consoles. But let's see the software attachment rates:

A bit outdated, but roughly it shows that there is no relevant difference between the amount of software

The above chart proves that either:

A)Casual gamers buy similar amount of games than "hardcore gamers".

B)The majority of Wii gamers are not casual.

2)

Another assumption is that casual gamers buy a few games, but they don't, or only rarely play them.

Question:

A) If you think that the A answers were correct, what is the point of calling certain ones "casual gamers", even though they buy games frequently, and play them regularly?

B) If you think that the B answers were correct, and the audiences of the listed games are not casual gamers, what would be more fitting example for them?

Well I would say A for both but playing regularly =/= playing alot. Regularly could mean 10-20 minutes every night. To me thats casual.

Weird opinion, I didn't even hear anything like this before, that casual gamers are believed to play in shorter sessions... 

Also, the avarage 35 hours of Wii Sports were played in ~29 sessions, that means longer than hour long sessions, and this is true for the other  examples as well.

The Nintendo channel is slightly skewed sampling, just because you have to be a conscientious enough Wii owner to connect your Wii to the internet, download the Nintendo channel, then access the channel and agree to have your usage stats shared (at least, i'm pretty sure that's how it works. Correct me if i'm wrong, please)

Either way, there certainly are degrees of casual gamer. My roommate has a 360, and all he plays are Modern Warfare, World at War, and NHL 09, and he plays them sparingly. Certainly would qualify as a casual gamer, but how does that differ from the proverbial "Wii Fit Mom" whose gaming portfolio might consist only of Wii Sports, Wii Fit, and Guitar Hero III, ?

I've been contemplating and developing my own thesis on how to divide up gamers by usage, to seek the root of hardcore, core, and casual terminologies, mostly in an effort to set the term "hardcore" back up on a pedestal that would eliminate a lot of the self-proclaimed hardcore gamers running around these days as actually hardcore, and to try and sift out the Wii Sports/bejeweled casual gamer from the Madden/Rock Band casual gamer

Whats so hard to beleive? My mom uses her Wii for about 15-20 minutes a day, that would be casual use. I play my PS3 an average of 3 hours a night, that would be hardcore use. So technically we would average 1 hour 40 minutes over 2 sessions. Its obviously 2 seperate consoles but I'm sure there are plenty of hardcore gamers who play the Wii. But that time is basically representative of the numbers you linked to. Over a months time the 2 of us would combine for 100 hrs, over 60 sessions in a 30 day period. Or an average of 50 hrs in 30 sessions over a 30 day period.

Casuals are people who like games that are so easy you could play them blindfolded and get pissed off easily at games and stop playing them instead of trying to get better.