Putting aside the rectitude of using a public e-mail service like Yahoo Mail for government business, as Alaska governor and U.S. vice presidential candidate Sarah Palin has done, if her e-mail was so easily hacked, how private do you think yours is?
The answer? Your only hope may be to keep so low key that no one cares about hacking your e-mail.
I'm willing to bet that most public figures keep Gmail, Yahoo Mail, Hotmail, etc. accounts, though most probably don't use them for public duty. Is it really as easy as wanting to crack them to be able to do so? The methods used are not yet known, but the hackers wouldn't have had much time. Despite it being somewhat common knowledge in Alaska that Gov. Palin uses private Yahoo e-mail accounts regularly, the news doesn't appear to have hit the national stage until the last week or so.
In other words, as soon as hackers had interest, they got access. This should be of concern to anyone using an e-mail service like Gmail or Yahoo Mail. Is our e-mail privacy only as durable as our anonymity? Security through obscurity, indeed.
Update: Ars Technica has details on a possible first-person account of how Governor Palin's email was hacked.