I have several sites (automotive) that leverage available content from third parties all above the board and we give them acknowledgement on the pages where they are displayed. We add other specific content that makes the mashed up content unique (in our opinion). But always being worried about the "duplicate content" issues it makes me ask if any knows if the alt tag content goes into the calculation of the uniqueness of a page's content? I have not to seen any penalty for any of my sites content for duplicate content as we add value in all we use of this content. But always worried we may cross a line we do not wish to cross. Thanks
Yes, it would have an impact. Google algorithms are parsing the source HTML for each page. This includes both alt tags and src filename targets. Vary up the alt tags and use synonyms instead.
I don't think that I have actually seen any metrics on this specifically, but that is certainly a fair statement to make. I would have to agree. Nigel