Google is overpriced IMO, their PE has been at around 30 for quite a while. At their size it's extremely hard, if not impossible to keep growth at level to justify the high PE. Google's PE should be around 15-20, max. Personally, I'd rather own MSFT, better diversified and offers a dividend.
Their SE is unbearable without ad blockers already.
It doesn't really make sense to compare this number with other companies in the same sector. Long-term, the stock price needs to reflect the actual income and growth of the company. Otherwise we are in "greater fool" territory. There is good reason to be skeptical of Amazon's valuation, and that of many other tech companies.
(Not that for the record, I am almost exclusively a growth investor in the speculative part of my portfolio).
Google still has room to grow, though. I am actually more worried about Facebook's risk/reward profile.
But I think their growth is artificial and not sustainable. It's obvious that their growth has been achieved by adding more ads to the pages even as their CPC is crashing. .
"Markets can remain irrational a lot longer than you and I can remain solvent." comes to mind ...I was right two years ago but Google continues to surprise me with their audacity and ability to suffer no penalties by users and governments.
But eventually everything will be ads and someone might notice ;)
Google has huge cash reserves ($60 billion), so you really should look at P/E adjusted for cash and cash equivalents on their balance sheet. Ex-cash, it's about 19.
Their SE is unbearable without ad blockers already.