One of four Sudoku titles
on Zango

Marketers looking to reach casual gamers online, take note: puzzle games, particularly number puzzles, are the most popular, according to entertainment site Zango.

MediaPost reports that out of Zango's 20 million users, five puzzle games comprise the site's 10 most popular games.

Gamers often enjoyed variations of the same game, meaning you don't have to have the most creative game on the block to garner participation.

One advertiser that leverages the trend of simple, single-person gaming is Wrigley's Candystand. Each game is roughly a variation of others played on childhood consoles such as Nintendo or Atari. And each game relies heavily on the characteristics of a given candy it is advertising.
For its part, Zango attracts a mature demographic of gamers. Sixty-two percent of users are over the age of 25; 25 percent are over the age of 45.