Thanks to SignpostMarv Martin for pointing this out to me today there is a easy fix for the SL Web Viewer experience.
- Visit http://interest.secondlife.com/beta – Wait for site to load up then:
- Replace the URL above with the following java link by visiting: typewith.me/EmSrDXPnFO
- This forces the success dialog to show
- Enter email and start exploring the new web-based experience (Works in Chrome & Firefox)