Yes, but Hotmail is an exception, I suppose because it is owned by Microsoft so they want Windows to have POP3 access to it. Otherwise what you are trying to do doesn't make sense. That setting in Internet Options is telling Windows what email client
to use to check your email. An email client is a program like Outlook Express, Thunderbird, Eudora, etc. There is no client with webmail, you're using your browser, not an email program.
Now if you have an email client you could set it up to retrieve your email if the webmail account allows POP3 access. It looks like you have to pay for a premium account at mail.com to get POP3 access.
Personally, I use an email notifying program called POP Peeper
to download and read email from multiple web-based accounts plus my email client. It's not exactly an email client but pretty close to it. Not sure if that is what you want tho or if mail.com is supported.
Edited by Papakid, 13 January 2010 - 02:38 PM.