The
only way you can tell whether your effort is worthwhile is to go over your server logs with a fine-toothed comb. If you're not already using
Analytics, you need to be; it's built to answer exactly the type of question you're asking. And it's free.
Without knowing what sites and pages your articles are winding up on, it's hard to say how Google will value the links. Potentially, they could be worth a lot, if you're putting them on sites with plenty of content, in good standing themselves. It sounds like you're sending them maybe off to individual sites instead of dust bins, or article directories? If there's only one copy of your article I think the link will carry a lot more weight, than if it winds up on a hundred sites Google isn't particularly fond of and all the pages land in the supplemental index.
I don't see any articles on your site, which is good
in a way, suggesting you're going about distributing them properly. You know, avoiding the shotgun approach. But you should consider holding onto the best articles you produce and publishing them only on your site. This will encourage your customers to see you as a more broad resource, and it will also bring people into you site through a new door.
But to answer your question, look for referrals from the sites where you're leaving the links. Without those, it probably
isn't worth your time. And look for search referrals to go up
slowly for keywords in the anchor text, page title, and Hx tags of the pages you're linking to. Getting back to Analytics, tracking users' movement through your site, and how different keywords are doing for generic search, is a giant help.
