It could be earnings but the estimate for 2013 is $1.50 in EPS. So it's trading at a 113 PE. Makes no sense to value it that way. Credit Suisse uses an enterprise value to unlevered free cash flow ratio. Currently CRM is trading near the top of those historical ratios.
On the revenue ratios the amount the market has been willing to pay for the revenue has been going down since 2010 where the market paid 13.1 times revenue. Now it's trading at 8.0 times revenue, but just last month it was trading at 6.8 times revenue and in the summer 6.3 times revenue.
AMZN is another crazy overvalued, no earnings company. It only trades at 2 times revenue. It seems reasonable to think this revenue ratio could continue to compress.