Good to see another alternative to the old notify service

It would be neat if we all could agree on a subset of POST data, that we all send, so that the same code could be used with any notify service, afaik theres 4 to pick from now.
That does not prevent each software from adding extra data, just as long as the basic data is what is used for signature verification.
That would also mean any shop modules could easily be adapted for each site.