Hi With article marketing is there any point is posting to a directory more than once? What I mean is once you have a back link from the site what is the value in a second or third back link from the same site?
It's exactly what you think it is. More links = more value, higher ranking and more attention. Every time you write an article you should be submitting it, regardless of whether you've submitted to the site before or not.
It's not just about that one backlink from that one site. Webmasters use my articles in their blogs and on their websites. These are the very articles they obtain from article directories. And it delivers targeted traffic. Also, articles featured in Ezinearticles.com frequently rank well in Google. (Depending on the keyphrase used.) So by listing your articles there, you're upping your chances of getting that back door traffic from Google.