I vaguely remember another service like that from the days I was still doing rails.

The pain is definitely real. We had a 6-year-old rails app that got upgraded from Rails 2.3 and keeping track of dependency decay was painful.

Looking at your landing page, I could not understand how are you solving the problem exactly. The screenshots don't expand so I don't really get the solution.

One very nice feature that you can add and will help a lot is to support comment parsing in the Gemfile and Gemfile.lock. Something like email: my@my.com. When you parse the file, send me the report and don't make me actively visit the page.

Also offer a sample report on your page by submitting a public repo perhaps.

Good luck!