The year was 2003 and I was in my second year of CS undergrad. I saw a cool utility in AOL instant messenger that recorded the username of every user that looked at your profile. I cloned it and added it to my profile. A few of my dorm mates liked it and asked me to put it in their profile. Even more people came asking and I made a simple website (buddytracker.us) where you could add the utility to your profile. I did no marketing but every profile using buddytracker had a hotmail like link to get your own profile tracker. The first month I had 30 users, the second 500, the third 5000, then 50000. The following year 3 million people had added a profile tracker. It was a life changing experience allowing me to pay off my student loans, travel and take a non-traditional career path. I work on side projects to this day and AOL is where I got my start.