"At a quick glance, I could have easily mistaken this site for something built out of Fab. If I were Fab, I feel I would be angry and want them to stop copying my work directly." -- If someone built competing search engine with a text box & search button, would you be confusing it with Google ?. Shouldn't people knowledge enough to differentiate & recognize brands by quality of service offered by them?. There are many clones of Instagram, Groupon, Airbnb. Systrom of Instagram told techcrunch,

"There might be 10 clones here, [but] there are also 20 clones from the United States right? You know, being copied is something that I think that every successful company will go through. Our biggest defensible asset really is our community, and I think that’s the thing that you’re not going to find on any of these replicas." (http://techcrunch.com/2011/11/06/instagrams-kevin-systrom-on...)

and Instagram didn't sue their clones !!.