Google can index and crawl PDFs, in fact many PDF’s rank well in the search results compared to websites built in flash. Google can actually index the content in the PDFs, however PDFs do cause the search engines some problems if you are not careful enough.

Many sites will use PDFs to create highly graphical images of their products or services, these types of PDF images Google struggles to understand just as it struggles to understand and rank images. It seems Google still heavily rely on the content.

You should try to create your PDF using a text based program such as Microsoft Word rather than Photoshop. Once you have created your PDF you should optimise it in a similar manner to how you would optimise HTML pages. Each PDF should have a title that is keyword rich, you should also write your content on the PDF to have a strong keyword density.

You should also optimise the meta data for the page, and include the keywords for the PDF in the file name, this will make the PDF more optimised and encourage people to click on it. If you simply want to use PDFs to duplicate content on your product pages, you should either noindex the page by adding a meta tag, or block PDFs from being indexed by Google.

In conclusion creating a fully optimised PDF can help draw more visitors to your site, whilst allowing a high quality document to be downloaded and kept by your visitors.