Because the web is so large and there is so much information, it is nice to have databases to limit and specify what you are looking for. Take for instance, looking for a lost loved one. My father's dad dies when he was very young and does not know any history, or past medical history about him. Just for the fun of it, I looked up his dad's name on the internet and came up with his social security number and birth date. Also, when looking for houses,you can specify the type, cost, how many bedrooms, and so on.
Databases make life much easier to limit teh information that is out there.