Why is it a bubble buy? They are getting in on the A round of every YC company with the same terms as the other participants and with their deep pockets the ability to lead A rounds as well as B, and C rounds for those that take off is worth way more than the $150k each.

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.

Basically, he's investing in everything that YC is investing in, except he's investing at much worse terms than YC gets (that is, YC typically invests in companies at a valuation of a couple of hundred grand, while Series A rounds are typically at a significantly higher valuation than that). It may, in the end, pay off, but I don't think it's a good investment strategy to follow someone else's investments and pay systematically more than they did.

He's getting much worse terms, but he's also doing a lot less work. YC picks the companies, does office hours, finds speakers for dinners, cooks the dinners, works out deals like this one and the Facebook one, etc.

The terms are only worse in the beginning, the YC organizers do not have a $1B fund to lead on A, B, C rounds and beyond. Because of the ability to double down on the winners the terms may actually be better than what the YC team gets.

People have been talking about how crazy deals he's lead have been already for several years. History has quickly proven them foolish.

Past performance, as fund managers are always obliged to remind you, is no guarantee of future returns.

Not the same thing at all. Most funds just follow the stock market's performance. They are at the mercy of the market fluctuations. What this investment is saying is that Yuri believes strongly that YC has the ability to pick winners more often then not. And they do it often enough that it's not even worth his time to do anymore diligence.

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.

it's not a guarantee, but it's very often a correllated indicator.