To be clear here, there is no such thing as an "10W" license. The FCC grants three types of licenses, each with increasing privileges. Any licensed person can operate at power levels up to 1500 watts for General and above, 200 watts for Novice/Technician. Operating at 10 Watts and below is a popular form of communicating called QRP. It does, however, still require a license. You also need to have a licensed individual at the far end if you want to have two-way communications. If they're receive-only, then no license is required.