Sodahead was a very popular, successful and very active Q&A discussion site - now a polling technology site for media companies.
It had a large number of members of diverse nationalities, various groups and topics, although largely centered on USA views and interests. But there were rumours about the site being sold (the CEO left in 2014?), and later on, it was closed down abruptly in June 2015.
Several former insiders are also here and on various other Q&A sites. Many "refugees" have settled on Facebook. As to the other sites, ask Dan; he is the expert and very helpful.
Info: https://en.wikipedia.org/wiki/SodaHead.com
The site: http://www.sodahead.com/
Business comes first: