Very nice!
FWIW, I don't share the hatred of registration that the others here do. I don't think it's asking a lot for an email address and a password after you perform a useful service for someone.
Thanks for this great feedback, and thanks for your point of view about registration, that's very valuable for us to have both sides, that's a difficult choice (anyway, inorder to offer the free monitoring,we need an email address!)
Ok let's take some time to create a temporary email address because, well, your product looks refreshing.
I put down the email address (the one I just spent time creating!) and a password. Your now reject my temporary email address as being temporary !
If I eventually give up, and give you my real email address, will you send my any email ? That one would be unsollicited, and you can be sure that people who created a temporary email address will mark your emails as spam, which may destroy your sender reputation...
People who give their real email address may not mark your emails as spam. But people who take the time to create a temporary email address will, with very high probability.
This is not helpful criticism in the least - most people don't object to sharing something as innocuous as an email considering they just did something nice for you.