Twitter & Search Engine Optimization (SEO) Value

Ever since I started Tweeting (which isn't too long ago), I've been wondering how the urls inserted into tweets contribute to SEO. So I started digging and thought I'd share my findings here on TechHui! If anyone has further insight, please post them as I am curious about this.

Before I start, when I say Search Engine Optimization, I refer to it in the context of getting a website ranked high on Google's SERP. One of the factors google considers when determining the order of SERP is the number of links a particular site has pointing to it (and associated keywords). This is why I wanted to know if Twitter had SEO value.

Summary of Findings
The majority of sources claimed that links within Twitter (301 redirect or not) don't have any direct SEO value because Twitter adds a "nofollow" attribute to their links. However, one source claimed that nofollow links actually "allow spiders to cache and index," so value is debatable. What is true at this point is that the links definitely contribute usage data to your site. That is a good thing in the eyes of Search Engines, so there is value there. A more indirect SEO benefit is that Twitter allows you to build brand recognition that could lead to more inbound links from bloggers and other websites.

Here are some more details in case you are interested:

Twitter's "NoFollow" attribute and SEO
"Twitter adds a “nofollow” attribute to links submitted by its users. The “nofollow” attribute advises Google, and a few other search engines, to ignore the link. Some of these follow the links but exclude them from their ranking calculations (Yahoo!, Google); some ignore the links completely (MSN). The only known search engine that doesn’t comply with Google’s “nofollow” at all is Ask.com."
http://www.sitepoint.com/blogs/2009/01/15/twitter-seo/

"..with the nofollow tags on these sites the link value can be debated. ... link value is still passed but at a much lower value. ... these links do get picked up and put into Google's and Yahoo's backlink checker and ...nofollow still allows spiders to cache and index, which is still great."
http://www.webpronews.com/topnews/2009/03/25/where-social-media-fits-into-the-seo-equation

TinyURL's 301 redirect passes Page Rank to Google but not for Twitter
"TinyURLs are dynamically created URLs that redirect users to the real URL via 301 (permanent redirect). Search engines do not index TinyURLs, but index and pass PageRank to the actual URLs instead. The problem with Twitter, as we already discussed, is the “nofollow” attribute added to all submitted links."
http://www.sitepoint.com/blogs/2009/01/15/twitter-seo/

What is Twitter's SEO value then?
"To make a long story short: although Twitter is a social media tool meant to create community and relationships, it does have an SEO value. For example, Twitter can affect positively your Alexa rankings by sending visitors to your pages. Usage data is a sign of quality for Google and all the other search engines. If you can make people come to your site via Twitter, then this is an SEO advantage you cannot afford to miss."
http://www.sitepoint.com/blogs/2009/01/15/twitter-seo/

"Building a presence in the social web is all about reputation and branding. Most of the web's top ranking websites maintain strong brand recognition in their respective industries. Strong branding leads to natural inbound links, and this is the lesson to be learned about building a reputation within social media networks."
http://www.webpronews.com/topnews/2009/03/25/where-social-media-fits-into-the-seo-equation