2. You need to be cautious of and properly handle notorious webspam/blogspam regurgitation sites like "recode.net":
"Wal-Mart Scammed Into Selling PlayStation 4 for $90" http://recode.net/2014/11/19/wal-mart-scammed-into-selling-p...
Which leads to:
http://www.cnbc.com/id/102197050
Which leads to:
http://consumerist.com/2014/11/18/terrible-people-create-fak...
Which leads to:
http://kotaku.com/people-are-scamming-walmart-with-bogus-che...
Finding the original source can be a PITA, but it's still much better than rewarding spam regurgitation sites with traffic.
3.) Having a "sign in" icon link on every single article listing looks odd. Is it the default replacement for some voting mechanism that's only available to logged-in users?
4.) Grey text on a white background is common fare on the web (including hn) to de-emphasize some text, but it's a poor design decision in terms of accessibility. People with even minor visual impairments (i.e. poor vision) have difficulty reading grey text on white backgrounds.
All in all, it looks interesting. Good Luck With It!