Both Google and Bing (with Yahoo SERP going to be powered by Bing they will really be one in the same) plan to begin indexing Twitter tweets in 2010. That will allow them to show the the tweets within the Search Engine Results Pages (SERP). This will more than likely be the first test for real time, non-paid, content to be indexed and shown on SERPs. That means you should position your Brand for more in depth, relevant, and timely tweeting because you will be able to move the bar on the search engines more quickly.
This will also help move Twitter from the social space into the main stream for business purposes because this will make it relevant on so many levels. Effecting real time search results? That is power. I would see Blogs getting the real time priority next(especially those using Blogger if you are Google) as they already help immensely with index-able content on a site. One would have to think that Facebook posts would be on the short list as well to go real-time