How do you read www.productmarketing.com?
Looks like Google Reader wins the contest for RSS Readers by a wide margin--at least for the readers of www.productmarketing.com.
And what do you do as a product manager when your competition has the market-leading position AND is free? I dunno. I think it means you need to look elsewhere for revenue. Instead of competing head-to-head with a dominant (and in this case, free) product, look for personas that are not well-served by the generic solution; find a niche that needs tailoring for their special needs.