There are two categories of plugins. Conversation Plugins interact with the chat environment itself. For example, with the event finder plugin, two people chatting can bring up a Yahoo map and find pegged restaurantes, venues, etc. to discuss them. Another plugin that I saw demo’d was the “avatars space” where users can interact in a virtual environment using avatars, pull in flickr photos and othe props, etc. The other type of plugins, Personal Plugins, pull content directly into the IM client itself. Users can add news, Yahoo 360, calendar plugins, etc. The idea is to pull core web services into the IM client, avoiding the need to open a browser.