From my experience, I have seen sites that have the exact keyword phrase in the domain do well for ranking with less effort (SEO), than other sites. I have also seen sites that have the keyword phrase at the beginning plus some other numerical characters rank well with less effort. By this I mean, for example Sitename1.com, or some other group of numbers. My question is, I have seen sites with numeric characters after the keyword in the domain do well, would and extra alphabetical character have the same effect? For example SitenameA.com I understand that a extra alphabet character could cause the domain to be interpreted as a different word, as the numbers would probably not do that. anyways, any information on this would be great.
I think this should have the same effect as using a number at the end. Google and other search engines will still notice the keywords in your url. Don't expect miraculous rankings just by using a keyword rich domain though. You will still need lots of quality links to get good rankings. A keyword rich domain just helps get your keywords in a greater percentage of your links.