laɪbnɪts was born because of the sheer frustration of not being able to find documents that you know you've viewed before. Something which is even more infuriating than trying to find an article in the first place!
This is true for individuals, students, groups of friends and companies. We all know how hard it is to keep detailed notes about something you are working on, especially when you really start to concentrate on the problem. In the middle of this focused work you often aren't thinking about the future. You may not realise that in one week, three months or a year you'll need to re-visit your research and re-find that crucial document! In short most people don't keep records of their research because it's simply too costly and tedious!
Machines are really good at collecting data. However, the web just isn't set up for the individual who wants to easily retrieve information they've spent time collecting. So back we go to the search engines and the cycle repeats!