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It is really likely that the penalty was because of anchor text over optimization. check you backlink profile for that keyword. do you have many domains pointing at you with that keyword? Remember that with penguin it the link profile have to look natural. For homepage most links should be the brandname, variations of the url, and links like here you can XYZ ... etc Only a few with keywords. Check your anchor text profile in OSE. Good luck!

This is good news sugar-coating bad news Thanks!

Yes - to both you and @MagicDude4Eva - it seems this is about the thin content as opposed to the index of products listed there. Page titles and URLs are indeed unique, but the content can certainly be worked on. Thanks a lot for your help

I won't be too hard on the programmers - I'm a programmer myself. Our small business has developers and designers doing the bulk of the SEO. I can see you've looked in to it as I have - there are many factors involved if I was to decide to "fix" this myself. To be honest, I don't fancy it - I'm hoping the better approach will come from the wonderful SEO Moz developers who might put in a fix. Hint hint.