It was an "online service", basically a dedicated client and a curated experience before the internet and web standardized things.

When you logged in, you'd get a "Welcome" screen with news, if you had any mail, etc. Most of AOL was organized into "Channels" which were different sections focused on things like Sports or Kids.

You could jump to a channel with a keyword, somewhat like a URL.

The channels looked somewhat like hypercard decks. Everything was designed to load fast on a slow modem and assets were shipped with the client, typically on floppy or CD. Occasionally a channel would download an "art pack" which could take 5-10 minutes, but this was rare.

After AOL 2.6 or so it had internet functionality and became an ISP. You still needed to use the AOL software to dial in (it didn't use PPP like others) but otherwise it worked fine.

It was the easiest "one of those" at the time, competing with CompuServe and Prodigy. Apple had a rebranded AOL briefly called eWorld.