I hear gaps of varying length between songs – what’s causing this?

Each song is stored as a separate file in the Internet Archive, so the app has to start a separate stream for each new song, and this involves some buffering of data, which causes a short pause between songs. But very long gaps (more than a few seconds) are likely due to congestion or data-limiting by your service provider; check their policies to see if this might be causing the issue.

How much of the data in my mobile plan will the Dead Of The Day use?

The recordings in the Internet Archive are of high quality and thus use a lot of bandwidth; the average bitrate is around 150 to 200 kilobits per second, or about 1 to 1.5 Megabytes per minute. Thus a complete concert can be between 200 and 300 Megabytes; if you have a limited data plan, you’ll want to monitor your data usage.