That is scary isn't it, which is why I don't use it :stuck_out_tongue:
but rest assure, there are tons of people using that command to stop the services permanently and we haven't seen them back here on the forums complaining, but then again .....
Anyways,
The services should be stopped .... theoretically :stuck_out_tongue:
You can always do the following...
/etc/init.d/wdphotodbmergerd status
/etc/init.d/wdmcserverd status
Remember you can use the update-rc.d for all the services to disable them permanently.
Finally, you can reboot the cloud to see if those services started up again.
Also I noticed that for the latest firmware, if you turn on the media switch, the services re-start themselves; very insidious indeed.