I just Yelped about the Lone Gull coffeehouse in Gloucester town, and about Good Harbor Beach. Five stars for each.
The photo is of course of said beach. The island is an island most of the time, but you can walk across the sand to it at low tide.
One gripe about Yelp: sometimes the details of a business give an obvious but wrong web address. For example, it gives lonegull dot com as the URI for the coffeehouse, and that URI is indeed in use, but for something completely different.