Bootstrapping to €600k MRR and getting killed by Shopify: Checkout X
"I built my business on top of someone else's product without any gurantee whatsoever of being able to continue in the future, and when it became valuable for them to stop me they did".Doesn't matter if you're a twitter client, a facebook app, a shopify app, a reddit client or whatever, either what you offer is negligible, or you did their research for them and now they can take over.