Using the chat divorced from the Video is against the terms of service.
But what about saving logs and only displaying them with the vods of a channel? That should be acceptable in the spirit of the ToS as far as I can make out.
Basically, will you shut down a site that embeds twitch vods with chat logs?
The NSA can do whatever it pleases since it can use the “national security” defense and it doesn’t expose the data on a public website and doesn’t plan on using the twitch API. I have none of these 3 benefits, so I’d like to know whether my efforts will be in vain before I spend a significant amount of time with this.