I don't think the comparison of P/E wisetech in 2018 and...

I don't think the comparison of P/E wisetech in 2018 and facebook in 2018 is valid because you are comparing companies at very different stages of their life.

Wisetec now is increasing the number of contracts and increasing the amount each contract is worth via upselling and selling new components. Think of that graphic with the different layers.

Facebook on the other hand is hardly increasing user numbers at all (particularly users with significant money to spend on the goods advertisers are advertising). It is gathering more information (so each user is worth more $), and more advertising money is moving onto the web (so the same % means more $ for facebook). However given the US election news and subsequent privacy regulation its hard to see that increasing at the same rate in the future.

I think the comparison to facebook 10 years ago (when facebook was in its growth phase) may be more valid, but back then facebook was still making a loss so didn't have a PE rating.

I think Amazon is also at a similar stage of growth to Facebook. Maybe a comparison with something like uber or procore in 2018 is more applicable.