The Squirrelmail web-based mail is not connected directly to the mail engine; it uses IMAP just like Thunderbird, Pine etc. to get your mail from the server and then presents it on the page. So everything you do with webmail is done the same way as it would be with a desktop IMAP client.
Users may wish to configure their mail clients (Thunderbird, Squirrelmail, Pine etc.) to use the same folder for sent mail if they use both methods regularly.
If you use someone elses PC to access your mail, they may be able to steal your password - either deliberately, or because their PC is infected with a virus. Exiting the browser after use should prevent an uninfected PC from staying logged in.
If you are truly paranoid about email security and privacy, use an end-to-end encryption tool such as PGP, and use it regularly so that traffic analysis doesn't show that you suddenly have secrets.
- Do not forget to log out after reading your mail! -