As a newcomer to this mode I'm pleased to report that I now have successfully RXed and beacon TXed on 30m using WSPR and my signal is being reported from around Europe (no further yet!). At the moment I am using QRO (5W) into my 28MHz wire halo (via an ATU) which is not an effective 30m antenna, HI.

WSPR would be very useful on 10m as an indicator of marginal openings.