Where to begin? I'll pick one of my favorite mistakes: Cleverly avoiding a market that was ripe for the taking. In the early/mid 90s I built a compressor call

Where to begin? I'll pick one of my favorite mistakes: Cleverly avoiding a market that was ripe for the taking. In the early/mid 90s I built a compressor called Quantum that outperformed PKZip by an average of 20% to 30%. For a few years it was the best-performing general-purpose compressor available. Microsoft, Borland, Novell and a handful of other companies licensed it. Cumulatively it saved them hundreds of millions of dollars in cost-of-goods for disks. My smaller mistake was to not apply for a patent. Quantum was the first compressor with a workable implementation of optimal parsing and about half of the improvement over PKZip was due to it. I was then (and still am) philosophically opposed to software patents but purely from a business standpoint possessing a patent on optimal parsing would have made it difficult for competitors. That said, I don't view the decision to not apply for a patent as being a mistake as much as a deliberate choice. My bigger mistake was to ignore the retail market. I felt that PKZip owned that and going up against them would be foolish. Instead, I took the low-hanging fruit of selling to software publishers. It was a handful of boutique sales (which one man could do) instead of attempting to penetrate the retail market against a strong, established competitor (which seemed intimidating.) Except... I was completely wrong. PKZip never made a concerted effort to build a usable Windows version of their product. Phil Katz didn't like Windows and so PKWare was slow to evolve the product from a shell wrapped around the DOS tool into a first-class Windows app. The world needed an easy-to-use compressor for Windows. An improved UI and support for additional compression formats extended beyond the scope of my original product but I could have done it without difficulty and I rejected the idea for the wrong reasons. The market was ripe for the taking yet I cleverly convinced myself it wasn't worth trying and settled for less. Fortunately for WinZip they didn't make the same mistake and they quickly rose to a dominant position.