Good point.

While anyone can share a video, I feel it adds ALOT more value to the share to include even a brief description of WHY it's being shared:

• what benefits watching it would pose to others in exchange for their time invested
• what impact its had on the person sharing and why they feel it's been of importance to them and may be to others

This really personalizes a share, and provides some good reasons as to why it's be worth watching, rather than just expecting people to watch