The video below explains how this new mobile web app, now in private beta, allows you to catch up on the tweets sent by people you follow in real time. This could mean catching up on a news story, journalism conference or a TV show. Indeed one of the promoted uses is to follow a hashtag, such as #bbcnews, and replay the Twitter conversation while catching up with the programme on the BBC iPlayer, 4OD, or similar.
Coles, who developed the app with Raak, details which parts of the service are free where users will require a subscription. There are also screenshots to provide a taster. There is also a write up on The Net Web.