I guess it was in the late '90s that I learned that the "right" way to send a URL via e-mail (or on Usenet) is

    text <URL:http://www.example.com>.

I can't seem to find that reference now (does anyone know?) and I don't know whether that practice is still considered "right", or by whom.

I either do that, recast the sentence so the URL is not followed by punctuation (as [Roger Attrill suggested](http://ux.stackexchange.com/a/15228)), or put a space after the URL:

    text http://www.example.com .

The latter makes me cringe, but at least the period doesn't show up as part of the URL. My preference is recasting the sentence (which sometimes means putting the URL on its own line as a blockquote).