Twitter is one of the most effective social bookmarking site, and SEO want his work advertising to promote website as his done. So twitter is better option for publicity work.
Yes twitter is useful for SEO because this is a famous social site and you can get good traffic for you site........................
With the new version of Twitter, you can search for keywords in tweets. This way you can target your niche easier if you own a website. Then follow that person or start tweeting to them. It's an excellent tool, I'm on there everyday.
also dont forget the potential of retweeted links ranking well in Google. seeing interest developments in these areas in the last two months
Twitter is not a source for increasing your website's search engine rank but its a great source of traffic for your website. You can gain a good and targeted audience from twitter.
What about SEO Keywords if you cant get backlines? I have a new website called 'sa-Businessnews'.com, I have a twitter name of 'SA business news' and I post links to recent articles. But I only have a handful of followers. Is this a valid strategy? PS. Does Google only pick up back links in the www. Format or will sa-bus......com work just as well?