We raise two challenges concerning the validity of arguments underlying Granovetter's strength of weak ties (SWT) thesis: (a) whether weak ties are actually bridges, i.e., they help reach more socially distant actors than strong ties, and (b) whether weak ties transmit information effectively enough so that weak ties’ alleged structural properties make them more useful than strong ties. In the course of reviewing subsequent research that has made progress in addressing these challenges, we identify both potential limits and possibilities for the SWT thesis. We argue for the importance of identifying how actors’ agency—i.e., the way people use their ties—may affect social networks’ value. We conclude by summarizing some outstanding questions that progress on the SWT thesis has generated.