In an arti­cle pro­fil­ing Google’s Marissa Meyer (employee num­ber 20), there’s this quote on Meyer’s views with regard to hir­ing practices: 

One can­di­date got a C in macro­eco­nom­ics. “That’s trou­bling to me,” Ms. Mayer says. “Good stu­dents are good at all things.”

Another can­di­date looked promis­ing with a quar­terly rat­ing from a super­vi­sor of 3.5, out of 4, which meant she had exceeded her manager’s expec­ta­tions. Ms. Mayer is sus­pi­cious, how­ever, because her rat­ing hasn’t changed in sev­eral quarters.

How­ever ser­ial entre­pre­neur Steve Blank says that aspir­ing entre­pre­neurs who don’t meet these stan­dards shouldn’t be put off:

What I remind [my stu­dents] is that great grades and suc­cess­ful founders / tech­nol­ogy entre­pre­neurs have at best a zero cor­re­la­tion (and anec­do­tal evi­dence sug­gests that the cor­re­la­tion may actu­ally be negative.) […]

There’s a big dif­fer­ence between being an employee at a great tech­nol­ogy com­pany and hav­ing the guts to start one.  You don’t get grades for hav­ing resiliency, curiosity, agility, resource­ful­ness, pat­tern recog­ni­tion and tenac­ity.