I am a graduate student of mathematics. I find the math.stackexchange.com site very useful in my understanding of mathematics. (I never used the site without mentioning about it in my homework, etc.)
Now, how do I include this site in the acknowledgement part of the master's thesis? Do I just mention the basic site name? Do I need to include the web address in the references part? There is no specific usage throughout the thesis. However, during taking lessons I benefited a lot from this site.