These days it’s easy and relatively cheap to spend hours on the internet. Sure, this is both a blessing and a curse but life would be incomplete without the world wide web. However, things were different back when the internet was still new, especially during the era of dial-up internet.
Besides the deafening connection sounds, you could also stay online just for a limited time. This OP clearly remembers that they had a daily limit of one hour on their AOL account but his sister soon discovered a way around it. Apparently, if you just unplugged your phone line during the session and logged back in, it would reset your hour.