I just found it. And testing.
Many years ago i was using Yahoo Answers, so stopped when it turned to demand phone number confirmation.
I checked other platforms like "Ask.com", "Stack exchange", "Quora", "Blurb", "Fluther", etc, but none with as audience, categories, multilingual branches as Yahoo.
Then, i met a platform called "Question2Answer" where you can create your own Q&A platform (Is opensource; but i don't know too much; looks like need to code and set in servers), with features like: - Post questions, answer/reply and comments with how many multimedia contents you want, like Youtube videos and images; - Tags (like here).
Unforntunatelly i don't know any QA site of this platform as big audience and variety of categories as Yahoo, just for niches (like Pokemon, etc).
(I'm still in quest)