What do we think of NetPromoter scores?

In a recent discussion with a client brand manager, the following question came up. "How do we track or develop a metric for posts online about our newly launched product?"

A number of national brands use Net Promoter Score to find out how likely an existing customer would be willing to recommend this product to another potential customer. NPS can be helpful in establishing benchmarks for ongoing eCRM efforts, but has it been too simplified to be useful?

Then I found this Satmetrix report was published discussing benchmarks across four different industries.

Can a lift in NPS demonstrate direct lift in sales? Please discuss.