No, it is not. It is mostly paid for by ads on the website. There are only a handful of SourceForge projects trying out this new, 100% optional, offer-based installer. PortableApps.com is not one of them. Bundling 3rd party offers is not permitted within PortableApps.com Format apps.
Edit: I am not saying portableapps.com is at fault here for using this free facility. SourceForge is, for their business model.