>>> I didn't know that this site is not a site in the US
We have mentioned it a few times!
http://www.theanswerbank.co.uk/Body-and-Soul/Relationships-and-Dating/Question1503352.html
;-)
>>> can someone tell me which site like this are used in the US?
Answerbag (which was one of the two biggest Q&A sites in the USA) closed down some time ago but is set to be relaunched shortly, so you might like to bookmark this link for future use:
http://answerbag.com/
At the moment the only major site in the USA is this one:
https://answers.yahoo.com/
(Some sections can be hard to find. For example, to find the 'Law' sections you need to go via 'Politics & Government')