superq7,
Congratulations on your decision, I'm sure you'll enjoy it once you've settled in after the transition from Windows.
You can also practice saying "Sorry my dear, got to go warm up the Maaac in my Jaaag"
Re: Contacts and Yahoo, I've never tried connecting contacts to Yahoo. But have you tried going to System Preferences -> Internet Accounts and setting up the Yahoo connection there ?
(For other readers confused about paragraph 2 above, cf. Clarkson thread in Jet Blast)