Q : I notice you always just show links to external URLs rather than make more meaningful and readable link text. Why?
A : Several advantages
quicker to bung them in. I don't need to use any special (even wiki) markup
can be easily copied and pasted into another browser window, email, search boxes, word processor documents etc.
easier to read in edit mode
you can see where the link goes to. For example, you can often recognise that a comment is on a particular weblog. That may affect whether you want to read it at the moment.
Q : Actually I now see you do occassionally hide external links
A : Yep, I've mellowed on this principle. Sometimes there are links with long id numbers as parameters, and these can stretch wider than the screen. Maybe a piece of useful design to make the text more readable, or maybe a bad violation of principle. I'll see how my feelings evolve on this.