This is your personal library of saved sound buttons and recent plays. Sign in to view your favorites and playback history.
The library is the short history of what you have actually used: the clips you played most recently, the sounds you saved, and the boards you arranged them into. It is built from your own activity rather than from a recommendation engine, so it stays short and stays yours — a handful of entries you would otherwise have to search for again.
Two lists on one page answer two different questions. Recent plays answer "what did I just use", which is what you want mid-stream when the clip you need is the one you played an hour ago. Saved sounds answer "what do I keep coming back to", which is the set worth putting on a board before a session starts. A sound can be in one list without being in the other.
Playback and MP3 downloads never need an account, so for a visitor who has not signed in this page has nothing to show — there is nothing remembered yet. Signing in is what gives the page something to hold: favourites, recent plays, and boards are stored per account, which is also why they follow you from a laptop to a phone. If you would rather not have an account at all, the sound index and the keyword soundboards cover the whole library without one.
A browser bookmark or a notes file does the same job badly: neither plays the clip, and neither keeps the title, the duration, and the source together with it. That is the reason the library exists as a page rather than as a list.