If you need support from Yola please contact us via firstname.lastname@example.org or make use of our live chat service! We are working on a new approach to community-based support and during this transition period we are not adding any new threads to this forum. Many thanks to everyone who has participated over the years and we look forward to unveiling a new peer-to-peer support system soon!
Just to help everyone out on this one: It is something we have already discussed and no, it is not technically feasible. There are a bunch of security issues and all kinds of ways users could break their sites.
Yola has no plans to offer PHP support, now or in the future. Sorry Nathan!