LinkedIn's announcement in 2011 that it was extending its social infrastructure across the broader web — adding a suite of plugins that allowed websites to display LinkedIn profile information, recommend connections, and facilitate professional sharing in ways modeled explicitly on Facebook's successful web-wide social graph strategy — marked a significant strategic escalation in the platform's ambitions.

Facebook's "Like" button, deployed across millions of external websites by 2011, had demonstrated the value of extending a social platform's infrastructure beyond its own domain: the button collected behavioral data, drove users back to Facebook, and embedded the platform's social graph into the fabric of the web itself. LinkedIn wanted to replicate this for the professional context.

The "Share" button for professional content, the display of LinkedIn connections' endorsements on third-party professional sites, and the ability to sign into external services using LinkedIn credentials were all part of a strategy to make LinkedIn's professional identity layer as pervasive as Facebook's social identity layer had become.

The strategic logic was sound: if LinkedIn could become the default professional identity infrastructure across the web, its value to both users and advertisers would compound significantly. A professional's LinkedIn profile, enriched by their behavior across the web and surfaced in the right contexts, was more valuable than a profile accessed only when users intentionally visited linkedin.com.

The execution would prove uneven — LinkedIn never achieved the web-wide ubiquity Facebook's social plugins reached — but the 2011 announcement signaled that LinkedIn understood the competitive dynamics of platform infrastructure and was prepared to invest in winning them.