Something I see missing from a lot of these startup discussions are the ideas of identity and community.
Sure, "solving a problem" is important. But Nike isn't solving a problem that other shoe companies haven't solved a thousand times over. The reason they're successful is that buying into their brand makes you part of a bigger community, and that community has a positive identity attached to it.
Same thing with a startup like Exposure (https://exposure.co/). Sure, the product is great, but they're also fostering a community and projecting a very specific image. Without that special "something" they'd be no different from Flickr or the countless other photo sharing services out there.
This brings me to Dinnr. Did you try to grow a community of passionate members organically by writing a blog, hosting events, being active on forums like whatever the Hacker News for cooking is?
Or did you just try to "solve a problem"?