What are currently the best architectural and deployment options for building and deploying a Dapp built with Meteor/Web3?
For building the Dapp, a few Meteor packages are currently available :
"Dapp Using Meteor" contains key Meteor packages
Meteor Build Client : https://github.com/frozeman/meteor-build-client
In practice, Meteor apps are hosted on a server. How can a Meteor Dapp be deployed so that all users who access it on the web can interact with the blockchain?
The result of Meteor Build Client should be static web assets (HTML, CSS, JS) that can be hosted on any web server or content delivery network. Aligning with the goals of a fully decentralized web, these files would eventually live on the Swarm component of the Ethereum network.
Strictly speaking, Meteor Build Client has nothing to do with Etheruem, however if using web3.js to interact with the Ethereum network, web3.js will need a node to connect to, either locally (i.e. in Mist) or via a proxy, such as with MetaMask browser.
