Here's what happens : When I search for one of my site's brand name, the first result is obviously the home page, and the second result is a PDF document (it's a data sheet of one of the products we're selling). This PDF document is supplemental. My question is, is it really bad? This supplemental result lets me secure two first results, doesn't it? Thanks for your help. PS I have already made a search and I have read a few articles about supplemental results. But they didn't answer this question.
Supplemental Results do appear in search results (unlike many here argue that they are penalised). Supplemental results could be because of several factors, some of them are 1) Duplicate content (which i think might not be the case in your example) 2) Result sensitivity to Keyword searched- This is important and i am not sure how many know this. If you search for your company name- if that displays 2 results which are high relevant however its obvious that your homepage has more relevancy than your PDF, in that case your PDF is supplementing your homepage. However if you specifically search for keywords related to your PDF document, i am sure your PDF will rank higher. Supplemental results are often supplementary to the primary keyword relevant results. Hope thats helps you and everyone else.
Thank you for your answer, godmode. I have tried searching for the product name. Just as well, I've got two first spots, the first one is the HTML page with some description (rather short one), whereas the second result is the PDF (labeled as supplemental as well). The two documents are not similar (the content is unique in both), I think the problem (is it really a problem?) might be caused be the fact that the titles are the same (Brand Name - Product Name). Do you think I should modify the titles? Or is it useless? I mean, right now the titles are 100% relevant... Decrease relevancy just to get rid of a supplemental result? Is it really wise?
slight correction to godmode's feedback Supplemental results DO APPEAR in search results, here is an example: http://www.google.co.uk/search?hl=en&q=walkiestime&meta=
gordano, i never said supplemental results dont appear. What i mean to say the "supplemental results" is just a result supplementary to the primary results. Doesnt necessarily mean its a penalty. reborn, you are heading into the right direction, as i said, duplication is an issue. It seem same title will definately go for supplemental results. How google determines that- title is duplicate but more backlinks by anchor text for homepage so homepage ranks higher. Just change title of pdf to something you want to rank for. i am confident that it will then be OK.