Twitter hasn't quite reached the popularity level of Facebook or YouTube, but the micro-blogging service is quickly becoming an essential way for brands to closely connect with consumers. With venture capital becoming scarce in these dire economic times, Twitter may soon resort to a pay-to-Tweet model for these companies.

"The VCs have the money, but they'll just negotiate harder," Twitter CEO Evan Williams told Bloomberg. "I want to manage things so I don't have to raise money in 2009."

Some of the options Twitter is weighing include charging companies that use the service to gather feedback -- such as Comcast and Amazon -- or perhaps including ads beside its search engine results.

Twitter recently surpassed 1 billion posts, so it's clear the micro-blogging service isn't going anywhere any time soon.