The dialup modem noises. Lots of text. Lots of in-line animated gifs.

My very first experience of the internet was when we got a modem at school. We were sent to the library in groups of threes to have a 'go' on the web using the one Acorn computer that had a modem. One of my group decided to try 'sex' as his first search.

Edit: Also, when we finally got a PC & modem at home (a little later than a lot of my friends) my sister and I were each allowed one hour online per weekend. That limit was slowly eroded.