Long ago, fanpop did briefly have the ability for users to pakia video to the site, but almost nobody used it, so the staff removed it about a mwezi after it was implemented.
So now users should use any video sharing site and then insert the URLs in the "Add a video" form. For zaidi information, wewe might read the
link.
That said, I would strongly recommend that wewe use a different video service than YouTube...depending on what wewe are trying to do. YouTube, now owned kwa Google, is constantly changing how video are handled and presented on other sites. In particular, YouTube is terrible for posting video to pop chemsha bongo maswali (the majibu to the maswali are usually in the title of the video, and now YouTube embeds the video title with the video on other sites) and also bad for posting video involving any content that might be copyrighted (music videos, movie trailers, TV onyesha clips, etc. - YouTube is very quick to remove such content, which then makes for broken viungo all over Fanpop). So, while wewe can use YouTube to post your own personal videos, if wewe want to, say, create a fanvid, I recommend posting it elsewhere, such as on Flickr, Vimeo, au Dailymotion.