#1 - Look at 2012/2011 [1] - "As of December 31, 2012, our worldwide portfolio consisted of 500 properties (135,144 rooms and units)".

Property has value, even without income. AirBnB has no such thing.

"[...]We primarily derive our revenues from hotel operations, management and franchise fees, other revenues from managed properties and sales of vacation ownership properties. For the years ended December 31, 2012 and 2011, revenues totaled $3.9 billion and $3.7 billion, respectively, net income attributable to Hyatt Hotels Corporation totaled $88 million and $113 million, respectively, and Adjusted EBITDA totaled $606 million and $538 million, respectively.[...]"

[1] Source: - http://phx.corporate-ir.net/External.File?item=UGFyZW50SUQ9M...

#2 - Your $30MM ($300MM) is before taxes, before expenses, before costs of expansion (servers, but also support, legal, etc etc) to get to the $300MM, and based on them not paying taxes, not adhering to local laws, etc etc.

In short: I think it's fair to state that the $10BB valuation is rather 'bubblelicious'.