[1] http://www.nytimes.com/2014/05/25/us/final-word-on-us-law-is...
It also has Selector functionality (in addition to full-page monitoring), which let's you explicitly choose which elements on the page to monitor for changes.
(disclaimer: I wrote it)
Do you have any plans to open source this? That's the big factor for a lot of organisations decisions as to whether they'll make use of software or not. For example we have a policy that we won't rely on any proprietary software within our build / test pipeline.
However, we expect that initially most will add Diffd as a manual step at the end of their pipeline. So, it's not like their ability to push code is completely dependent on a third party, it's just another check.
Taking a dependence on Diffd is going to be less risky than depending on a third party for your CI server like Travis CI, CircleCI or CodeShip.
You might also be able to achieve a similar sort of backup with Cloudflare.