There’s an interesting post on the Google Mobile Blog explaining Android’s Gmail-based email and contacts system. It’s pretty long and detailed but the basic gist of it is that you don’t need to sync your contacts. Ever.
The moment you use Android Gmail or Contacts, everything gets synced automatically to the Gmail server. Everything you send and receive, as well as everyone you know is automatically saved and accessible from anywhere you can access Gmail.com. This simple idea instantly makes traditional USB connection kits, driver installs, backup programs and PC syncing software look rather archaic.
The downside to all this is that it currently only works with Gmail. Hotmail, Yahoo and Exchange users will have to wait till someone else adds it in.