The blog post announcing it covers it pretty well (although briefly):
Per Piero’s post:
“This move is designed to continue guaranteeing the software freedom of our users in a world of ever-increasing cloud services. Despite some questionable claims of the otherwise, by certain large organizations, AGPL is an excellent license for an open source project such as OpenDroneMap (as this humorous blog post by Drew DeVault explains). This choice will continue to help OpenDroneMap be as open and inclusive as it possibly can.”
Per the linked post:
In truth, the terms of the AGPL are pretty easy to comply with. The basic obligations of the AGPL which set it apart from other licenses are as follows:
- Any derivative works of AGPL-licensed software must also use the AGPL.
- Any users of such software are entitled to the source code under the terms of the AGPL, including users accessing it over the network such as with their web browser or via an API or internet protocol.
I’m short: AGPL only requires that you share any code changes to OpenDroneMap back to your users via the same license. Usually, the easiest way to do that is via contributions back to the project, but other options are available including direct sharing.
Per Drew’s post about AGPL:
The Google page about the AGPL details inaccurate (but common1) misconceptions about the obligations of the AGPL that don’t follow from the text. Google states that if, for example, Google Maps used PostGIS as its data store, and PostGIS used the AGPL, Google would be required to release the Google Maps code. This is not true. They would be required to release their PostGIS patches in this situation. AGPL does not extend the GPL in that it makes the Internet count as a form of linking which creates a derivative work, as Google implies, but rather that it makes anyone who uses the software via the Internet entitled to its source code. It does not update the “what counts as a ‘derivative work’” algorithm, so to speak — it updates the “what counts as ‘distributing’ the software” algorithm.
I hope this helps clarify things. I am not a lawyer, and this does not constitute legal advice, but the AGPL license terms are pretty clear. Players like Google have muddied the waters a bit by making what appear to be false claims regarding the copy left aspects of AGPL.