The only guidance that has been given by Google from this appears
to be in the form of tweets.
As already discussed, Google’s social media responses can often
be misinterpreted.
Verdict: Officially? It’s a myth.
Unofficially – there does seem to be a period of time whilst Google
tries to understand and rank the pages belonging to a new site.
This might mimic a sandbox.
HOW TO SPOT SEO MYTHS: 20 COMMON SEO MYTHS, DEBUNKED