I created the first version of W3Counter back when good web stats were something you had to pay for -- before Google Analytics existed. That I did mostly for fun; I loved watching the hit counter of my "resources for web developers" site going up, and wanted to see all the new visits as they came in and what people were looking at. I added a bunch of new features and reports in 2006 and 2008, and updated the design a few times, but it's not changed a whole lot since the beginning. Somewhere on the line to picking up ~80K users organically, I decided to monetize it by offering paid subscriptions for some extra reports and e-mail summaries.

Improvely's basically the result of taking a side project and writing it from scratch a second time to try to build a serious business out of it. I was running a kind of marketing business and needed to track the performance of my ads, but I was poorer back then (in college) and didn't want to pay for any of the existing conversion tracking tools. I built a (horribly named) link tracker called W3ROI that did everything I needed, and paid a web designer to make a sales site for it to see if I could sell it to anyone else on the side. It never made enough to be a primary source of income, but I learned enough from the customers it did pick up, and reading some great stuff on HN, to do better the second time around when I wrote Improvely over the summer of 2012.

I have another side project that might go somewhere. A relative of mine opened a retail store, and I helped out putting together their e-commerce presence and getting a shopping cart hooked up to their physical inventory system. In the process, I built a neat little contact form plugin for that e-commerce platform, with some unique features you don't normally see in contact forms. I threw it up on that platform's plugin directory and it's now actively used by more than 11,000 other stores, delivering thousands of mails a day. It's got hundreds of perfect reviews in the plugin directory, and two companies have approached me about acquiring it. I'm thinking about monetizing it somehow, but haven't had the time.

Same post from January 2015 for a reference.