errgh writes "I'd like to start a web service that eventually would be supported either by ads and/or a subscription fee. It would be based on a open source social portal backend, although I will have to do some serious modifying to get it do accomplish my goals. The software is GPL v2 licensed. What will I need to post so that the license requirements will be met? Will I need to provide dividends to the authors? Can I not disclose the modified source, but only the unmodified original?"