One good reason not to is that a 100/1 PE ratio is very high if your assuming $1b profit and a $100b cap. In comparison Google has a P/E of 20, and Microsoft 11.

Those reasons you have given are basically a gamble on the assumptions that:

- Facebook can earn a lot more money (5x - 20x more)

- Facebook hasn't done it yet because they haven't figured it out

- They will figure it out within 3 years (your exit window)

It does seem like an overly simplified argument. I don't think monetising Facebook to the levels you think possible in a 3 year window is as easy as people think, and it might not actually be possible.

You're also ignoring the possibility that this gamble isn't already priced into the stock.

Yes, but is any of that not already priced into the stock? The folks who have been buying and selling huge chunks of FB stock for the last few years have done a lot of thinking about that sort of thing.

I understand when a startup, like Instagram acquiring eyeballs and saying: "we really don't have a business model, but when somebody will acquire us - they surely will figure this out".

But when Facebook saying "we didn't really started to monetize our 800M eyeballs, we just waiting for IPO and will figure it's later" - it's sounds silly.

They never said that. It's just their actions. They generate enough cash to sustain themselves and they can grow. They are doing it properly and taking their time.

Just like Twitter is.

You may poo poo it all day, doesn't change the fact that over the long run it works.