"Casual" gaming is a phenomenon by which demographics that do not normally care to play games become regular gamers. Regular could mean with friends, before bed, after dinner, on the weekends, during lunch breaks, or every day. Also, casual gaming means that the player has a very narrow perception of the gaming industry and gaming culture at large. If a player is so heavily involved with a Facebook game that they spend multiple hours per day on it, but this is the only thing they play, they are a casual gamer. If someone plays two hundred franchise years of Madden every year, but that's the full extent of their gaming, they are a casual gamer.
Now that "casual" has been clearly defined within the context of gaming, let's get on to the pressing issue: casual gaming is the new cash-cow of the gaming landscape. For some, this is of no concern because they have no interest in casual-style games. For others, this is a sign of changing times and great worry, because the gaming enthusiasts are no longer the core audience for many publishers. Free-to-play games dominate social websites like facebook, and more still are found on many free-to-play websites.
Casual gaming seemed to creep into the gaming landscape in the early 2000's with the launch of websites like addictinggames and newgrounds. Suddenly, parents, teachers and other professionals were playing games for free, from their web browser, and having a good time about it. Launching animals and other objects, falling columns of multi-colored jewels, bouncing balls and pinball machines were lighting up millions of browsers, and a fad was born.
I believe Nintendo was the first major-league gaming company to take note of this phenomenon, and take appropriate steps to capitalize on the newfound curiosity and urge to game that crept into the consciousnesses of millions of non-gamers. The Nintendo DS was released with, and continues to be supported by, a multitude of games aimed towards older people, professionals, women, and other typically non-gaming demographics. Brain Age, Big Brain Academy, Sudoku are just for starters... the DS is a playground for publishers trying to make the next big hit with the out-crowd, and unfortunately, the Wii has turned into a similar conduit for such "shovelware."
As previously mentioned, many of us gaming enthusiasts with a passion for gaming and playing many kinds of games are concerned because games can now be commercially successful and rake in millions of dollars for the right party without fancy graphics, cutting-edge engines, or years of development by a dedicated team. A few guys in a garage can now feasibly crank out an iPhone game that will sell millions and millions of times with the right combination of gimmick and accessibility. As such, many gamers are worried about being left in the dust of the fiery, money-spewing chariot that is casual gaming.
The most recent developments in the race for dominance of the casual gaming market are PlayStation Move and Microsoft Kinect. Each of these peripherals are fully-functional with each company's currently supported console. The PlayStation Move is attempting to capitalize on the disappointing aspects of Nintendo Wii. Sporting a nearly-identical motion-sensitive controller, Move claims to be very sensitive to player movements, giving it more applications than sports and party games. Kinect is doing away with controllers altogether, utilizing hardware that recognizes bodily movement and photo-recognition.
Regardless of which is the superior platform, one thing is sure: casual gaming is a gigantic base of people, waiting to be exploited to buy millions of units of hardware and software alike, and therefore spending much of their money. Given the escalating quantities of killer games in the past six or so years during the fall season, 2010's fall lineup of heavily-advertised and hyped games consist largely of games that are exclusively for use with the motion-control peripheral.
Enthusiasts' worries are justified that they may fall from grace as the crowd to please, only to be replaced by their mothers, little sisters, and grandparents.