"No one has cracked the code when it comes to ad-funded mobile gaming in the U.S. or Europe. There's a substantial enough opportunity to capture experimental ad dollars, but I don't see mobile games becoming a real solid part of the digital media mix yet – at least not in 2008," said Seamus McAteer, chief product architect and senior analyst at M:Metrics, according to Media Post.

M:Metric’s report pointed out that although more mobile subscribers are playing games on their phones, the number of users that have actually downloaded a game, which is typically the ad-supported operating model, is still relatively small. Only 14.4 million, or 3.3 percent of subscribers in the United States and Western Europe (France, Germany, Italy, Spain and the United Kingdom) downloaded a game in December 2007, which was even lower than 14.6 million (3.6 percent) in December 2006.

According to McAteer, the reasons why users choose not to download mobile games include pricing concerns, difficulty in finding games, and the lack of effective marketing information on the games themselves.

"The extent to which games are merchandised on handsets is limited. Most of the time it's just the name of the title and one or two lines of brief description. And if users aren't able to try the game before they buy it, they are less likely to make a purchase," said McAteer, according to Media Post.

In addition, some may feel the trial version of a game preloaded on a handset is enough. "The free version provides ample entertainment for people who are occasional casual gamers," McAteer said. "And if the experience is sub par, then they're not going to take the risk of buying another one." McAteer also pointed out the lack of knowledge of the pricing models – such as whether users are charged for minutes while they're playing free games, and whether the carrier charges extra just for the download, Media Post reported.

McAteer added that although some companies have tried to bridge the gap between consumers, service providers and advertisers, the process of finding and playing ad-supported games is still a problem for users. Without the critical mass, the ad revenues will still be relegated to experimental budgets. "All advertisers care about is reach – when they start seeing reach in excess of 10 and 20 million, then it gets kind of interesting for them."