Several questions about Mozilla Thunderbird

1: Using Thunderbird is probably as safe as using a browser to access mail via a web interface. Probably safer if the browser in question is Internet Explorer. For the others... In some ways it's probably safer, and in other ways it's probably not as safe, so it comes out as something of a wash.

2: No, not really. Both Microsoft and Yahoo sell POP3 access to their mail systems as a value added sort of thing. They don't offer it with their free services like Google does (for now at least). It's generally best to respect the wishes of these companies on this. At best, if you try and get around it, they're likely to delete your account without warning. At worst, they could charge you with hacking into their systems. In a time when the President has been using the terrorist boogyman to create an environment of fear to prop up ever sagging approval ratings, and distract from some large and embarrassing military blunders... Large corporations have seized on the opportunity to screw over consumers in new and interesting ways, all in the name of preventing terrorism. Even if the connection is even more dubious than what the current Administration offers up.

If you don't believe me... There was a case of a guy in Michigan who was fined $400 and given 40 hours community service for simply sitting in his car outside a coffee shop to check his email with his laptop. He was using the coffee shop's wireless Internet connection, which was supposed to be only for paying customers. Despite the guy clearly being in the wrong, the penalty seems to have been overly harsh if you ask me. You can read about it for yourself here:

http://www.theregister.co.uk/2007/05/23/michigan_wifi_conviction/