[grey-area]

This isn't just about time, though that's also really cheeky of you since the plumbing is the sole value you provide, who would sign insane terms like this?

You shall not...use the Developer Tool or Service in conjunction with a product or service that competes with products or services offered by IFTTT

IFTTT shall own all right, title, and interest (and all related moral rights and intellectual property rights) in and to the Developer Tool, Service, and Content.

Perhaps Pinboard should come up with some equally crazy terms and ask you to sign it in order to use their service.