Ok, I've been selling software online for almost 10 years. I have had several products marketed to both individuals and businesses.
I am always shocked when I see developers are happy that someone thought their software was worth stealing. I mean, didn't you already know that? Why else would you spend time creating it if you didn't think it was worth anything?
I'd wager you would not say, "Wow, I had some great stuff and feel honored someone went to all the trouble of taking it." if someone broke into your house and stole your property. Stealing is stealing no matter if it is a Porsche 911 turbo, music, software or a pack of gum.
There is also another popular myth that pirated versions do not impact sales. I have done a few different experiments myself and also have friends in the industry that have seen significant revenue impacts due to piracy.
In fact, I had one product that I could always tell when it was keygen'd because sales would immediately dive as much as 70%. I was using partial key verification, and when I updated the verification to make the bogus codes stop working sales immediately went back to normal. I assume you would call thousands of dollars a month a significant impact on sales?
In one experiment I used the partial key verification to redirect customers who entered a pirated key to a special web page that explained they were stealing.
Guess what? Over 50% of people who went to that page bought the software. That almost brought sales back to pre-keygen levels.
Those people would have stolen the software if the code would have worked for them. This is a product with a fully functional 30 day trial, so they had already fully tested the software. Also, the product was under $20 USD, so it wasn't an expensive one.
Other people I know have tried the redirect bogus codes to a web page technique with similar (and sometimes significantly better) results.
I do agree that some people will never buy your software, and you have to balance protecting unauthorized use and inconveniencing honest customers.
But don't be fooled into thinking piracy isn't a big problem and not worth investing a reasonable amount of effort to prevent. People aren't as honest as most of us would like to think.
Update
First I want to say, as I stated in my comment below, I am not going to get into an argument or debate about this--especially one based on semantics. I have debated this for years in person, at conferences, and in private forums. I've heard all the arguments before.
Now I will try to answer some of the constructive questions.
I tried my own experiment on two different products.
One was an Outlook add-in to manage various hidden security settings. It was purchased by both individuals and companies. The numbers above are for that product.
I also did another experiment on a business targeted product that translated database schemas to various formats. This product had slightly less (around 10% less, so 40%) conversion from the page I redirected the bogus keys to.
I also am aware of several business owners that did the same experiment and discussed the results with me in private. These were a wide range of products. Some had a vertical market and some were very horizontal. Their conversion rate on the bogus key page was between 20% and 70%. Even at the low end that's a significant amount of extra revenue.