I would like to offer up some advice. Do not apply if you're simply applying because it's good practice, or you're gambling against the odds. You won't get selected. If you've applied 4 times before and did not even get an email response or invitation to interview, then you should probably evaluate why it is that you apply each go-around. The folks at YC have obviously tuned their process finely enough so that it avoids candidates like this. I have a good friend who made it into YC years ago, and for several years after I tried getting into it myself. I found friends to apply with so I'd have a group, and we came up with company ideas that we could apply with. I tried this probably 3 or 4 times. All times, I coded my ass off in hopes that it'd end up with a trip to YC for an interview - so, it wasn't all just empty applications. But, was I really applying because I had a startup in need of that extra push? Was I in a position to make use of YC's advice, had I even gotten in? Maybe, maybe not. All I know is that I felt like I was applying just for the sake of it. Sort of like it was some free contest that I could enter, and if I won it meant instant fame and fortune. Well, let me break it to you softly ... do not do this because it only ends in the same place that it begins.