My first team at Google was solely focused on helping people connect with each other on Google's social platform, Google Plus (G+). These projects had a direct impact on social ties, or what we called: "edge growth" -- as benchmarked by the company.
The people notifications system I created increased edge-growth by over 30%. To this day this was the single most impactful product feature to be launched on G+ driving more connections than any other feature or integration. This feature still exists in product today and showcases "You may know" suggestions when there are no people to add back.
Post unseen was a highly controversial attempt to surface new people via their latest post. The hypotheses was that if you saw a preview of the content you're missing, you'd be more likely to add the person generating it. We wanted to surface no more than one post at a time from people the social graph had indicated had high affinity to you. Because the stream is a place for content from people you've deliberately added to specific circles, this was a tough sell. We pitched over 30 different design variations, and only launched to a small % of users in the end.