If a URL is too long to fit in your window, but less than a maximum length of about 127-128 characters, it just makes your virtual window wide enough for the URL so you have to scroll horizontally to see it all.
If it's longer than that, it makes the virtual window that width and breaks the URL into sections of that length. You have to scroll, plus if you try clicking on the URL your browser only picks up the line you click on (and only recognizes the first line as a URL, since the others don't start with the right letters). To use the URL you have to copy the segments after the first and paste them after each other, one at a time.
By the way, this doesn't just apply to URLs. Any really long word would do the same. The reason we only see it with URLs is that English words are usually not long enough to make it happen.
As for the question in your subject line: with the proliferation of toolbars, palettes and everything else in every application, you
always need a bigger screen!
(edited to fix minor typo)
[This message has been edited by Efrem (edited 10-01-2001).]