Recently, I have finally chosen the licence for the YASEP project : it's the Affero GPL as published by the Free Software Foundation.

It is practically the same as the GNU GPL but with one interesting twist : You have to provide all the (derived) source code if you use it on a server.

For the YASEP project, it's not a problem because all the "intelligence" is provided by client-side JavaScript code, and the rest is static or dynamic HTML (not server-generated pages). However, using the AGPL is a clear sign that YASEP is not just a bunch of RTL files packed with documentation pages. It is a living, dynamic, organic set of files that interact with each others...

Also, I would like that eventual contributors keep the structure of the files and directories, so the whole archive remains available to anyone visiting the sites. YASEP directly provides the link to the current archive on the main page, and I believe that this is a good thing that others will do in the future.

Concerning the VHDL source code : since the only difference between AGPL and GPL is the server clause, well, I distribute the RTL files with AGPL too. One licence to rule them all...