World's Knowledge - you are chatting directly with Large Language Models (LLMs) without interrogating any content you've uploaded. When you ask a question or make a request, the response you get is based on all the data the LLM has been trained on. In the case of Open AI's GPT-3.5 and GPT-4, that's all of Wikipedia and much of the internet.
All My Knowledge - you're chatting with all the knowledge that's been uploaded to your personal profile, or, if you're in org view, all the knowledge that's been uploaded to your entire organization and made accessible to you.
What about tags? Want to chat with a specific document? A tag? A group? Learn more about how to do that in this post.