Webmail should not be used as your main email client. It's OK to use webmail when checking email from remote locations; but don't trust webmail to store emails and address books. SquirrelMail is a more stable webmail client.
Mail clients such as Windows Mail, Outlook Express, Thunderbird or IncrediMail are very user friendly and more stable. IncrediMail is free and can be easily backed up.
Thunderbird works well with normal folders, but has some issues with custom folders containing email disappearing when moving them.
Some ISP's block the Outgoing SMTP Relay causing outgoing email messages to bounce. If you are having trouble sending out email, please follow the instructions below.