Earlier quoted context omitted.
No, not only. You can host software packages and tutorials on your product website. For example, patio11 of HN fame has an article about Rails SEO Tips on his product website http://www.bingocardcreator.com/articles/rails-seo-tips.htm Even though I'd say that he could have done a better job at integrating it on his website (it looks too much like an isolated page in my opinion - there should be a "Tips for developers…
That's sort of what I mean. For my work I build and run a number of websites which are almost completely unrelated to tech. These are service industry websites so there is no "product" to speak of. I am looking for ways to improve pagerank, so let's say I was to write a few pages about how I built some of the trickier parts of these websites and hosted these on the websites themselves but perhaps did not link these t…
By getting links to your articles you'd improve overall authority of your site (also important to link back to your homepage and other important pages in order to drive PR back, as you point out).
By improving your website's authority you'll rank better for your main keywords as well.