We have extensive experience in all 3 categories as our current product does exactly that: https://app.x23.ai. 
We scrape and aggregate data from a number of sources, both via APIs and generalised scraping, condense that information, then curate it by apply our ranking algorithm to the content.
The result is a newsfeed of information that users can sort by the latest / chronological order, or by the most controversial (as ranked by our algorithm).