GPLv2 only stipulates that you must distribute your modifications to GPLv2 code to your customers. There is nothing in there about giving code back to the original maintainers.

However, those same customers, under rights given by GPLv2, now have the right to redistribute that modified code, so they could make that available to the original maintainers or anyone else. I think it is this viral clause that makes the GPLv2 such a brilliant legal document.

Companies that do not provide their changes to their customers are breaking the GPL and deserve exposure and vilification. This is the *minimum* requirement of playing in the GPLv2 field.

Yet, it is *not* a GPLv2 requirement to give changes back to the community. However, if you "play nicely", your organisation will garner a lot more respect and be more closely aligned with the core projects if you do. Everyone wins in this scenario and you reduce your risk of being vilified.

I gave a speech at the Nagios Conference in Germany last year (http://www.netways.de/de/nagios_konferenz/archiv_2006/programm/open_source_etiquette/) where I argued that it makes good business sense to give your changes back. And I want my company, Altinity (http://altinity.com), to be an example (http://altinity.org) of how you can play well (http://source.altinity.org) in the open source field, specifically for Nagios.