What does this website do?

It attempts to give you recent and upcoming tide times for tidal areas in the lower 48 states of the United States of America. Maybe it works, maybe it doesn't. It may give useless or misleading information.

What about outside that area?

It may work in (or near) some other US states and territories. It may give useless or misleading information.

Who maintains this website?

Ambrose does. You can attempt to contact him at ajhwxx@gmail.com.