@ormaaj asks in slack:
Why is this a browser extension? Is anybody working on integration with system resolvers? I assume evetually one should be able to specify `order hosts, bind, blockstack’ in a host.conf for instance.
Blockstack isn’t a browser extension. It integrates with system resolvers and provides a locally running web app users use to manage their names and identities.
Ooh…kay, so this is interesting then. I just read some talk in the blog / elsewhere about “browser extensions” and “custom browsers” and assumed the whole premise was to go around normal host resolution with some hacked web broweser that mangles DNS or something - but that’s not what was meant by “browser”. I’ll rtsl next time. 
No worries! We’re giving a lot of thought with how we can make Blockstack compatible with existing DNS. Very happy to get your feedback and participation!
Does that mean that blockstack is just an identity management tool? or is it going far beyond that to integrate apps that use the identities for authentication and data storage?
Identity management is part of it.
Think of it this way. Your existing Operating System (OS X, Linux, whatever) and your existing browsers (Chrome, Safari, etc) know how to talk to the traditional DNS and get IP addresses. Your browser also knows how to check security certificates and fetch content over HTTP.
For the new decentralized Internet your OS and browser needs to know how to talk to the blockchain-secured DNS, fetch and verify ownership using public keys secured by the blockchain and so on.
So the Blockstack installer “patches” your OS (by running new processes on your OS) and “patches” your browser by telling it how it can talk to these new locally running processes and manage private keys and identities etc.
All of that is done pretty seamlessly and the user just downloads and installs Blockstack and then boom! they can now access the new decentralized Internet.