The theory behind the 'Bermuda Community Resort' is not exactly hard to decipher. Basically the residents and visitors are various characters from television or movies that have (at some point) died. We as fans refuse to believe this. So, instead of dying, they go off to Bermuda to either live (residents) or visit (visitors).
And since this little pet theory started in the Buffy fandom with Jenny Calendar and Alan Francis Doyle, they are the resident founders of the 'Bermuda Community Resort'.