Fair enough. Imagining myself as an investor I would be concerned that it would be hard to get traction as an additional social network and it sounds too tightl

Fair enough. Imagining myself as an investor I would be concerned that it would be hard to get traction as an additional social network and it sounds too tightly tied to Google (Earth and Youtube) so I would struggle to see exit options apart from sale to Google and incorporation in G+. Given that I would be doubtful that a large exit would be possible as there is only likely to be one buyer so no bidding war. Now you may have plans to migrate away from Google dependency as you grow and actual VCs may have different views on these issues than me, I've been known to be wrong in the past ;). Instagram got $1BN while heavily tied to Facebook and Apple although they were launching their Android app at the time.