Yuri Milner definitely guaranteed his spot in future articles about the '10 bubble.
Consider this acquisition costs, like buying a really expensive key word on Google. The ~$6M every 6 months is worth it for the seat at the table. An additional benefit is getting to see the terms at which all of these rounds are financed at -- this will help them ensure they are paying properly on non-YC deals they get in.
He is saying that if he spent a bunch of time on each company the odds of him doing better then YC has already done is not worth the extra effort. He is betting he can get a good return by just trusting PG and company's judgment. Pretty awesome endorsement, imo.