We present in this paper the extended online HI-AUDIO platform which relies on a distributed and iterative music recording paradigm to asynchronously record musicians localised at different remote individual sites. The major goal of this platform is to become a key enabling tool for building a large, varied, multi-genre, multi-track, multiinstrument music dataset, to be ultimately publicly distributed for MIR research purposes. We describe in this paper the main characteristics of the web platform and discuss some of the major challenges for collecting music data on the web. The platform will be demonstrated on site with local and distant access and illustrate its merits for recording collaborative compositions.