SearchFox to Fold

My preferred RSS reader, SearchFox, will cease to exist in 2 weeks.  Esteban Kozak writes in his blog:

Thanks for all your help in making SearchFox what it is. We have enjoyed providing this service, and hope that you have enjoyed using it. Please export all of your links and an OPML file with your RSS sources before the site shuts down. In accordance with our privacy policy, we will delete all personal information on January 25 after we shut down the services.

Mike Arrington over at TechCrunch notes the RSS reader space is very competitive, which could be an explanation.

Since I read so many feeds every day (or try to, at least) I love the fact that SearchFox learns what I like.  I found that function to be pretty effective at allowing me to stay on top of the things I cared about most.

Hopefully, other apps will build in similar functionality.  I'd also be interested to hear Esteban's explanation of the decision to give up.  Was it a business model issue?  Was it simply too much competition?  Was it a scalability issue?