Yeah folks, we're getting SERIOUSLY OT here as this is a thread about "Non-Donna Summer Requests", which is ironic in that not only was this thread started because the Donna Summer thread was going OT, but Steven Wilson is not here to take requests for 5.1 remixes as he mixes what he wants to from what he's offered.
But, I absolutely must disagree with Keenly on the point that Engineers "love" to compress the hell out of mixes and masters purely for their own enjoyment.
No, that's not why it's done. It's done because many artists like their music to compete at the same or higher volume than their competitors on CD, radio, and online.
Engineers are beholden to whoever's got the money and is commissioning their services. Sure they might be able to persuade their clients that more compression/limiting is not always what's best, but at the end of the day, what the artist wants, the artist gets.
And to answer wavelength's question, the answer is both. I'll use compression at the mixing stage to shape the sound of individual instruments and the overall mix, but when mastering, I use compression mostly to limit the dynamic range and get it louder than it was in its purely mixed form.
It's absolutely true that compression & limiting on top of compression & limiting can sometimes do damage to the sound of a mix or master, but compression in itself is NEVER a bad thing when used correctly IMO.