If youre always on the move and a big Thunderbird fan, then this program should answer a lot of your prayers. Thunderbird Portable can run from a USB stick and leaves no hard disk footprint meaning you can use it with ease anytime, anywhere.The e-mail client is one of the most useful features - you can take your e-mail with you wherever you go although obviously, you can quickly fill up a flash drive with e-mails as you download them. Fortunately, the program itself only takes 30-40MB of space. In terms of performance, there are few noticeable differences between Thunderbird Portable and its big brother. Its really easy to install although we found synchronization with the mail exchange could sometimes be troublesome.