Chrome Extension

I need a chrome extension that can grab some content from a specific website and store the information in a manner that is easy to interact with. The website offers unique identities each with their own XML feed. My goal while browsing the website is to easily be able to find and add these identities and their associated feeds to the app. I want the extension to poll the feeds from time to time so that I can view latest content in them. I also wish to be able to attach messages to the unique identities, and for those identities to be able to respond to such messages (if they use the extension). Finally - each user should be able to add their own identity to the app and verify that they own it...