"I believe search advertising linked to the new search box on user's profile pages could have been an interesting revenue generator and that Twitter could have found the right balance so that ads would not be intrusive to the experience," she added. "This would have worked well, in my opinion, along with the model of charging for premium services and applications."

Dangson noted that she suspects avid Twitterers - say, the top 5% to 10% -- might pay for additional services and tools, but the majority of Twitterers will simply continue using the free services.

Ezra Gottheil, an analyst with Technology Business Research, noted that a historical lack of users "stickiness."

Last month, Nielsen Online reported that while people are joining the micro-blogging site in droves, a whole lot of them don't stick around for long. In fact, the online research firm found that some 60% of new Twitter users do not return to the microblogging site the next month.

That, says Gottheil, is going to be a problem long term when it comes to making money.