What do you think of single page websites?

It depends on what it's going to be used for.

If you're wanting to just have a single page for like an advertisement then yeah sure, other than that I don't know about single pages.

To add: Most advertisement sites don't do too well. AdWords, Facebook, Instagram are usually your go to.

If not at all related to an advertisement site then I would vote against the use of a single page website.