15 seconds?
Without specifying your location, the specific date (because I may be reading your question much later than you post it), and the specific conditions of the fast, this is unanswerable.
You must post a clear and direct question, and only the question, in your title.
To post a question without misspells, read the question before you submit it.
Go to forums> game play>post a new topic type in your question and a title for the the post
What time did you post this spacey post?
It does not have to be very fast at all. The computer may take time to fully load the video depending on length and what the video consists of, but chances are if you can post a question on this site you can watch youtube videos.
That depends on how fast people post the questions. And on how fast the question gets noticed, how quickly a person types, etc.
Do what you just did, with a different question.
You do what you did to ask this question.
uhmm?
uhmm?
Click on A:Answer question located on the bottom of the question.