From Bulbapedia, the community-driven Pokémon encyclopedia.
Frost Cave was part of the Articuno Island (AKA Prussian Town Pokémon Network), the former hostee of Bulbagarden. It was one of the leading Pokémon fan websites of its time. The site was started and maintained by a user named Dragonice. After Dragonice left Frost Cave on October 15th, 2000, the site was no longer maintained. Its lifespan was approximately a year and a half.
Dragonice's farewell statement
The main evidence remaining of the website is Dragonice's farewell statement, which can be here (the second post down). In his farewell, Dragonice announces that he will no longer be maintaining the website, initially claiming that he "doesn't have time" to run the website, then citing the Pokémon Company's decreased popularity, before finally going into an all out attack on the current state of Pokémon community, saying that he is "absolutely disgusted with the state of the Pokémon community today." He criticizes webmasters of Pokémon fan sites for only seeking to make a profit and have their website get several hits. He believes this priority has taken away what has made Pokémon fan sites fun.
However, he does end the statement on a much more positive note, discussing a variety of positive aspects of the Pokémon community, such as fan sites like Pokémon Forest X. He then continues to thank a vast number of people, and say that he will continue to be working with Bulbagarden and Articuno Island.