Semantic Scholar is described as '(paywall free) is a science publication aggregator that collects citation-data from PubMed, CiteSeer, IEEE etc and rank each article according to the percieved number of impactful citations' and is a academic research tool in the education & reference category. There are more than 10 alternatives to Semantic Scholar, not only websites but also apps for a variety of platforms, including iPhone, Android Tablet, iPad and SaaS apps. The best Semantic Scholar alternative is Google Scholar, which is free. Other great sites and apps similar to Semantic Scholar are ResearchGate, ResearchCollab, Connected Papers and Snowball.