MOTM

I'm using Outlook 2000---same thing.

The Email reader has some "intelligence" (note the hairy eyeballs there)
that tries to second-guess the text and make it "better." For instance, if
an Email comes into Outlook in plain text and has a word flanked by
asterisks, it will hide the asterisks and boldface the word, according to
convention. Same thing with underscores; it italicizes the word.

Special characters are also substituted: typewriter quotation marks for
typographic ones, double hyphens for an 'em-dash,' and so on.

If you put the full, proper URL into an Email (or a properly-formatted Email
address for that matter), Outlook will recognize what it is and
automatically convert it into an active link. It has nothing to do with the
computer platform, as was pointed out. It's the reader software.