Just a new study backing up what was already known but with real numbers i.e. they compare viral load in upper airways.

Asymptomatic individuals have comparable upper respiratory viral load compared to symptomatic patients.  So both are viable at similar levels, thus are contributing to community spread.   Hopefully being asymptomatic  they wont be sneezing so much, but that is countered with the fact you are probably happier going within 2m of someone that appears perfectly healthy, so don't drop your guard around apparently healthy friends.

https://thorax.bmj.com/content/early/2020/08/28/thoraxjnl-2020-215042 - https://thorax.bmj.com/content/early/2020/08/28/thoraxjnl-2020-215042