Why http://feedproxy.google.com Coming in Search Result

Hi Guys,

I just noticed that every post from Mashable site is coming in search result as well as the same post coming in top of search result via feedproxy.google

http://feedproxy.google.com/~r/Mashable/~3/9jyfRMKWdJg/

Why this result is coming in Google? it's just a redirection to original post and if its coming in Google result. Why not results from my blog feeds are coming ?

Why only Mashable? I did not see it for any other site.