I'm not sure I've got a fully formed concept here, but I'm throwing it out in case someone finds it interesting.

Re: long-tail movements and switching contexts between work and home, I wonder if a better example isn't much better user or persona management. Every person is interested in more than just one thing, and can conceivably be looking for the same word in two contexts. Down below, a multi-lingual speaker has given up on predictive keyboards.

What if we could enable users to switch personas/contexts as intuitively and easily as people code-switch in real conversations? Setting up the profiles would be messy and cumbersome at first which probably kills the idea dead in my hands. I'm not knowledgeable enough about psychology or machine learning to figure out if that could be solved automatically.