"All our social meetings involve some sort of fig leaf of catering and refreshment," says Mitchell.
New episodes of Soapbox are available to watch and download via YouTube, Facebook, iTunes, downloadable apps and other formats.
Meanwhile, sponsors ChannelFlip & Dell have launched a competition to find the "next David Mitchell" via the Comedy Spots website.
Winners of the contest will receive £10,000 and a year's development deal with ChannelFlip, including coaching with Mitchell himself.
The top five videos voted for by the public will join five picked by Mitchell and a panel of judges will pick one outright winner at a London ceremony later this year.
"So who exactly are we to sit in judgement?" quipped Mitchell.
"Maybe you want to think about that before entering this so-called 'competition'? And best of luck to all!"