A newspaperish grid layout hardly seems like something that's unique enough to go around accusing someone of ripping it off from you. Or did you rip off the New York Times et al?
If someone rips you off, improve on it and have the better product. It's too bad that your apps are so similar -- but the concept, layout and elements are old-hat. If he ripped you off on purpose I highly doubt he'd be eager about the HN community finding out about it.
* Use of a certain layout style which is literally centuries old.
* Prefetching content, an extremely common practice in computing.
* A similar font.
I think you need to seriously reexamine the originality of your work.