The biggest challenge for any cell-phone application developer is the fragmented nature of the market: each wireless network uses different technical specifications, so even an application written in a supposedly universal development language like Java 2 Micro Edition (J2ME) needs to be tweaked for each phone offered by each carrier.

"In the phone, Java is not as compatible as it is on the PC," says Joacim Boivie, CEO of Stockholm-based Mobispine. Mobispine is now available for 57 different mobile phones, and next week will add the RIM BlackBerry to its list.

Mobispine will also add new blogging capabilities, Boivie says. Right now, users who shoot video using their phones cannot post it to their blogs. That will change in about two weeks, he says.

IDC's Ward says it's unusual to find applications that circumvent the cellular carriers entirely, in part because it adds a level of risk: cellular carriers can ban communications out of their network. Thus, if Mobispine is too successful in selling ads to its blogging site, it could risk seeing its users cut off from their blogs, since cellular carriers tend to resent third parties who make money from their networks.

Another issue that may hinder Mobispine is that it hosts the blogs -- so people who are currently bloggers can't post to their existing blogs. Boivie says there's no technical reason why the company couldn't let them do it, but "we think most users don't really care where they have their blog."

Instead, he's betting they'll care a lot about blogging on the go.