HT Games
You're likely thinking of Froot Loops Island, a virtual world game launched in 2005 based on the popular Kellogg's cereal.
Players created avatars to explore a tropical island, play mini-games, and interact with others in a child-friendly environment. The game featured Toucan Sam and other cereal mascots as guides.
The official servers were shut down years ago, but you can still find gameplay footage and nostalgic discussions on YouTube and gaming forums. Some fan projects have attempted to recreate the experience, though none are officially affiliated with Kellogg's.