Successful software exists to solve a problem; be it boredom or too much stuff. One way to drive traffic to your site and improve your search engine ranking is to write a helpful guide to solving the problem without your software. It is important that you actually offer solutions, not just describe why the problem can only be solved by your software. Many ISVs don't have enough helpful content available, and those that do often post it to their blog, where it is fragmented and hard for a first time visitor to read. It is worth writing a separate guide that covers the basics and posting that outside your blog. A guide not only drives traffic, it can be an integral part of your website.
Once you have a guide written, consider using that content to create a lens on Squidoo and a page at eHow.com. While you can't just paste it in, you should be able to adapt your content quickly. In addition to the SEO benefit of inbound links, this thread suggests reasonable amount of traffic is flowing from Squidoo.
To take a concrete example, LinkedCells lets users share Excel data. We've been working on this guide to sharing Excel data. It is challenging to strike a balance between offering options on how to distribute and consolidate Excel data, and hoping that our advice leads the reader to try LinkedCells, rather than finding an alternate solution. Our solution is to describe all the options available from Microsoft, but not to discuss competing third party solutions.