We address all three of these issues you discussed at Blockstack:<p>1. Limited scalability and latency.<p>While latency is an issue, it is only an issue if you rely on all data and transactions to be on the Blockchain. At Blockstack, we register domains and identities using the blockchain and allay the majority of priority associated with these issues by solving the following two issues:<p>2. Limited privacy<p>We enable users to have their own data stores to whitelist app developers to write data to their own data stores, so users can then choose to render their photos, blogs, or what have you to the app developers, but they can then revoke access and own their photos, and render them to instagram version 3 persay to another app developer using the Blockstack API, and API that takes care of the complexities of interacting with user identity authentication and user data store, so the web developers can use javascript or whatever other web languages they are comfortable with to access user identity and the data for their applications, leaving users in control of their identity and their data.<p>3. Storage constraints<p>Storage constraints are significant if you rely on the blockchain to store all of the data in an application, but this is unnecessary if the user owns their data, and the identity that is proves they own their data is stored on the blockchain. The constraints of the data is truly decentralised by the user, where the user also owns their own data, contributing the alleviation of the privacy issue above. The only thing that is not private is their identity, making it hard to compromise.<p>4. Unsustainable consensus is a broad term that implies democracy is expensive because it requires computers to verify that things happened. While the old and outdated argument that bitcoin is energy expensive does prey on peoples conscious, it handwaves away the fact that most of the countries this bitcoin energy usage ranks above are third world countries where citizens not only do not really have access to computers or modern technology, but many of them democracy or human rights in general. I am glad that the consensus mechanism behind bitcoin does not rank below countries where humans have no access to technology or democracy.<p>In regards to the expense, ASICS are becoming more energy efficient, just like most computers are more energy efficient than they were 30 years ago.<p>How much energy do Facebook and google data centers use? Do you tell people they are killing the trees every time they check their facebook? Do you even know how much energy facebook data centers consume? To what purpose anyways? You wouldn't know.<p>Read more here: <a href="https://docs.blockstack.org/" rel="nofollow">https://docs.blockstack.org/</a>