I always loved sites with a karma/merit system, because by design, the users will get good content. Digg were the first link aggregation service to make this format popular. Users upvote what stories / resources they think are worth gracing the main page(s) - and those URLs enjoy a surge of traffic and attention. A quick Google yielded a few surprising alternatives to the usual suspects of Hackernews, Reddit, and Digg:
Hacker Street http://hackerstreet.in/
Data Look http://datalook.io/
Build Box http://buildbox.co/
A few other noteworthy ones:
Feel free to sign up to those sites if you have a few minutes each day to submit quality content. The more 'karma' you earn, the better. In and of itself, 'karma' is not worth much - but it goes a long way if you want to slip in the odd plug for your own content. Users tend to distrust those users who drive endless attention to their own product / brand. The rules are simple: Give give give, and seldom take.