Share your Android apps between devices

For those of you currently in a buying frenzy with the 10c Android Market Apps, be aware that you can share apps with people you trust by setting up their device with your Google Account as the Primary Account.

I have done this with 3 handsets in my Family (remember to turn off all the auto-syncing of the Primary Account's Email, Contacts and Calendar), then add a second Google account (and turn on syncing for that account) for the actual handset owner's Email, Contacts and Calendar.

Alternatively, you could set up a "dummy" account and buy everything on that account and set up your own actual account as the secondary account, thereby maintaining your privacy for all your private data.

I'm unsure how many handsets can share the same Primary Account.