Ah ICQ... how I miss thee. I remember first subscribing in the late nineties as I had just moved to a new city and was looking to make some new contacts on the way.
One of the best features (ironically would be considered one of the most perverse nowadays) was the people search function. You could literally narrow down your search to sex, country, city, online status!
I remember having 10+ chat windows all open at the same time, as one endeavoured to make new friends and acquaintances in a strange new city!
If I hadn't used ICQ back in the day, I wouldn't have met the person who eventually introduced me to my future wife