Without an open source license, open source is just published code. Open source licenses are what allow users to use your software, and more importantly, to modifying it (and hopefully propose improvements).
As of today TestingConferences.org is licensed under the MIT license. After having read the above article, it seems like a smart move so we don’t have to think about copyright or patents.
The MIT license is “A short and simple permissive license with conditions only requiring preservation of copyright and license notices. Licensed works, modifications, and larger works may be distributed under different terms and without source code.”
You can read the license here.