If you just can't get enough Sumana, and you're already reading my column and my del.icio.us subfeed (with comments!), check out my entries at the newish Fog Creek non-Joel weblog. I tend to talk about things that come up here and applying principles I read in books.

Competing with Open Source talks about how to honestly, fairly get people to use your proprietary product rather than a FLOSS alternative.

Don't forget that competition intensifies over time. Your competitors will watch your software improve, and copy it, and there will come a time when you can't make money off it anymore. Open source developers are great at cloning. Good software takes ten years but then it's done, and you will have copycats every step of the way -- open source and closed source. In the long term, we hope that customer service, brand reputation, and other stuff outside the actual codebase will give us an advantage others can't duplicate.

There's more stuff in that vein in Why FogBugz Competes Against Corkboards. And in Customer Service: Tools, Techniques, Training -- And Breaks I talk about the training, techniques, tools, and breaks we get at Fog Creek that help us support customers better.