I changed a tiny 15 second video clip section into a small GIF format (audio gets removed) and then made it even smaller by deleting every other frame and posted it in the Humor section...
You can understand why regular video cannot be allowed in a small forum ...file size too big and continuous looping.. storage size and bandwidth available would be used up quickly and slow things down and eventually crash and burn.
Youtube must have an UNBELIEVABLE storage capacity investment and budget. A marvel of the 21st century.