Data aggregators and directories are important roles in the ecosystem. There is so much data out there, that it's hard to keep up with what is available. Additionally, you want to ensure that the data feeds you want can be integrated with your existing data with minimal effort.
In the age of internet, big data has just become more commonplace and accessible. And it is growing, fast, and at astronomical rates. Every time we log onto the internet, every time we post on Facebook or Twitter, or purchase something on Amazon or EBay, or just do a Google search, we leave a trail of data. And all this goes into the databases of these websites or companies.