As part of the test, we will move good and poorly performing Hubs over to subdomains. We've tested this a bit already. With a 301 redirect Hubs regained their rankings when moving within a few days.
Our expectation is some deep links to Hubs won't pass all the link authority through a 301, but a substantial amount will pass. This is one of the tradeoffs as part of the test we are looking at to understand. Once moved, Hubs will be logically grouped by subdomain that will help them be evaluated more independently from all the other content on HubPages.
We've heard over and over that one of the benefits of HP is having a lot of the search engine optimization built into the platform. We will also be testing new accounts with original Hubs to see how they perform as well. There is evidence here that they will rank well for long tail keywords, but we don't have enough data yet, so this will be an important part of the test. In the past, a new hub for a long tail keyword on a good piece of content could quickly rank on the first three pages in the search results and move up over time. We'll be tracking this.