Aswath Damodaran points out that the Online Advertising sector may as whole be overvalued. If you trust his projections then the question becomes “which companies are the source of the overvaluation?”.
I’m not sure who the culprits are (if any), but note that $GOOG has the highest market cap on the list: projected to have about half the future revenue ($147 B out of $303 B projected/imputed for 2023).
Hard to judge price momentum, but $GOOG could be fully valued here on a valuation basis. Time to consider taking some profits.