Work and learning are essential facets of our existence, yet women have and may continue to face multiple restrictions that hinder and impede their professional outcomes. These restrictions are especially pronounced in the technical domains of Information technology and Computer science. This paper explores the power of informal online communities to act as collective shields of care in the context of professional development, especially for women. Using a mixed-methods comparative investigation of 400,268 conversational traces from three professional development communities on Reddit, we report resilience and communal empathy-building tactics, as well as calls for inclusivity and belongingness, which drive the collective identity of these online channels. The long-term goal of this work is to address the way in which such channels can be designed and curated to offer spaces for enrichment, empowerment, and advocacy with a focus on the professional development of women, especially those engaged in technical domains.