I'm just confused because I see so many sites that aggregate RSS feeds. It seems like almost every site is doing it now - especially those sites like popurls.co

I'm just confused because I see so many sites that aggregate RSS feeds. It seems like almost every site is doing it now - especially those sites like popurls.com and alltop.com. I emailed a handful of the companies whose feeds I am planning on using to see if they could elaborate a bit more. Thanks again.