This document discusses and compares several professional social networks for researchers, including LinkedIn and ResearchGate. It provides information on the features and approaches of each network. LinkedIn is highlighted as the largest and most full-featured network for professionals, with over 200 million users. ResearchGate is described as similar to LinkedIn but targeted specifically for researchers, allowing them to self-archive papers and datasets, find collaborators, and build their reputation within the network. The document also notes some typical problems with ResearchGate, such as redundant publications that cannot be edited and a high volume of irrelevant questions.