10-Year-Old Software Making $500 a Month on Autopilot
About
TSR Watermark Image is a piece of software designed for quick and simple batch watermarking of photos.

The Creator
TSR Watermark Image was created by Anders Thue Pedersen in 2009. Anders Thue Pedersen is the sole person working on this project.
Business Model & Revenue
TSR Watermark Image is downloadable software that you purchase and use on-premises. It used to generate approximately $3,000 per month. Nowadays, everything is done online. Despite being an aging downloadable software, TSR Watermark Image still generates a nice $500 a month.

Reference: https://news.ycombinator.com/item?id=10881967
Traffic
The majority of its traffic, besides direct, comes from referrals. The top referral site is https://xranks.com/, a software directory. In the early days, web directory submissions were a popular way to distribute software.

Should You Compete?
Watermarking technology has advanced significantly, and this task can now be accomplished online. People no longer need to download software for this purpose. We do not recommend pursuing this type of software anymore.