I am trying to build something similar and I was wondering if there are any legal issues with showing content from the source website into mine, in your case for example the content is the user's comments.
Except as expressly authorized by Y Combinator, you agree not to modify, copy, frame, scrape, rent, lease, loan, sell, distribute or create derivative works based on the Site or the Site Content, in whole or in part, except that the foregoing does not apply to your own User Content (as defined below) that you legally upload to the Site.
I really wonder if I need to ask for permission from each website about showing some text from their website into mine?
In this page https://www.ycombinator.com/legal/ under the Intellectual Property Rights is written:
Except as expressly authorized by Y Combinator, you agree not to modify, copy, frame, scrape, rent, lease, loan, sell, distribute or create derivative works based on the Site or the Site Content, in whole or in part, except that the foregoing does not apply to your own User Content (as defined below) that you legally upload to the Site.
I really wonder if I need to ask for permission from each website about showing some text from their website into mine?