ResearchGate is the world’s largest professional network for scientists and researchers with more than 1.3million members. With access to over 45million abstracts (not full text!), Researchers can search through 7 of the largest databases and millions of smaller ones simultaneously, including PubMED, Cornwell University & CiteSeer; by using the
literature search at http://www.researchgate.net/literature

They also have the largest science and research specific job board in the world at http://www.researchgate.net/jobs/research/?nav=jobs

As well as the largest Science and Research Conference Board at http://www.researchgate.net/conferences/related/?nav=conferences

They also featured in the New York Times on Tuesday; the article is really good for explaining what ResearchGate is all about! http://www.nytimes.com/pages/science/index.html