If this (screenshot of UI) is what people are paying $250/m for, and it's the best thing around then it looks like room for a simpler web based solution.
The market is the biggest problem - mechanics probably don't have a decent internet connection at work to start with, don't want to learn new software, and wouldn't even think to look for new software.
Im not sure about that. How many mechanics in the world are there ? A lot. So even if a small percentage have internet and are willing to try new stuff it could well be a market that is worth tens or hundreds of millions. Maybe.
How many mechanics have email ? I think a large percentage.
How many people starting up new mechanic businesses are in their 30s or even 20s and reasonably net savvy ? I imagine quite a few.
Course these questions are best answered with some research and discussion with mechanics.
Do you think it is spammy ? I think it adds value. What happened was It occured to me as a useful thing to post and then I considered which of my websites to put it on.
I think google does a pretty good job of providing good incentives. I mean there are a lot of people competing to create content that other people are interested in. That's a lot better than many of the alternatives.