B2B Startups Cloudant and Clustrix Enter Y Combinator Index Top 10

I wish the exact methodology that was used for this ranking is public, because it will help non-YC start-ups compare themselves accurately against this list.

The factors that goes into this ranking like 3-month Alexa Rank, Inbound Links, Facebook Likes etc.. are lagging indicators of a company. I wonder what the leading indicators could be. Maybe, current pipeline?