I wanted to add a suggestion that it's not necessarily wise to post your 'best' articles on sites other than your own, at least when it comes to
SEO. An article is considered duplicate content as soon as it appears on a second website - and this literally waters down the effectiveness of your text, your keywords, etc.
Something to bear in mind when submitting articles.
I do think it can be useful in terms of getting others to pick up your content [it gets your name and voice around] and just in terms of getting people interested in you, establishing yourself as an expert, etc.
So, what you have is two types of articles, or three really - the ones you submit for the sake of branding, the ones you submit for
SEO purposes, and the ones you keep on your own site. Personally, I'd recommend keeping the best of the best on your own site and/or in ezines and other publications that go out to a mailing list and/or ONLY on the best sites [ie - industry-related sites, high
PR sites, sites with a lot of traffic and exposure etc.]