This comprehensive Google+ SEO guide covers every aspect and angle of Google+ and how it impacts search.
Most of the attention is on the integration of Google+ in Google search results. However, internal search on Google+ is a fascinating product and lays the groundwork for search integration.
Google+ search queries return results with a standard selection of facets.
Sometimes Google selects these facets for you. Specifically, it will default to People and pages for many queries. These are generally category or head terms like SEO, Photography, Chef, CEO, Gardening etc. But a query for something like ‘banana bread’ will not return a preselected People and pages facet but just provide an Everything feed of content...