This article uses a social capital framework to examine whether and how the use of three types of publicly accessible social media (LinkedIn, Twitter, Facebook) is related to professional informational benefits among a representative sample of Dutch online users. Professional informational benefits were conceptualized as the (timely) access to relevant information and being referred to career opportunities. The effect of content and structure of the respective online network on professional informational benefits was examined on the general (users vs. non-users of a platform) and more fine-grained level (within users of a specific platform). Overall, users of LinkedIn and Twitter reported higher informational benefits than non-users, whereas the Facebook users reported lower informational benefits. Posting about work and strategically selecting ties consistently predicted informational benefits. The network composition mattered most on LinkedIn; strong and weak ties predicted informational benefits. The results demonstrate the usefulness of the social capital framework.