Any ideas related to the techniques for building the content aggregators' architecture?

I am working on thesis that is about content aggregation systems' architecture. The research focuses on techniques for building their architectures. Could you please share your ideas on that?

What do you think is the most actual problem in building the content aggregation systems? I mean, content aggregators as the distributed highload systems, of course.

What are the patterns for the evolutionary development of such systems, from a small project to the a large distributed system?

Thanks in advance. Any help and your thoughts are appreciated.