Is it just me, or do they crop up more frequently?

Needs some sweet Humble Sega Bundle

Almost every week. The first one where you could get Batman AC GOTY and Binary Domain for $15 was awesome. The previous one with Civ V and Spec Ops: The Line was good too. So far Get Loaded and Amazon have kept me from even considering buying from Steam this season.

So much for their market dominance increasing prices ....

Ah I forgot:
DotEmu has a FunBox catalog sale, with a lot of nice games:
http://www.dotemu.com/en/pc-games/discounted
for usually $2.50

The Civ V one was spectacular. The equivalent would be Shogun 2 with all its DLC and Fall of the Samurai as a second option.

(I totally would have grabbed that, if it was available)

The awesome aspect of Steam that keys can be sold elsewhere with no money going to Valve keep it from being a traditional monopoly.

Steam has to get something. It's their bandwidth. They must be paid somehow.

And as I always say, piracy is the de facto guarantee that you can get a monopoly in gaming. Every service competes with piracy. And the most successful have actually emulated piracy (GOG and Steam), as in "hassle free gaming".

Pretty sure I have read that they don't. The benefit to them is everyone loading Steam constantly and seeing what they sell, I would guess.

I think Valve charges a royalty fee for games using Steamworks, so they get paid no matter where the key is sold, otherwise why would Valve pay for the bandwidth for nothing?

The payment is publicity. Valve sees every game registered on Steam as a potential new customer that will be exposed to their store. I'm too lazy to look for it but their Steamworks site for developers states that every retail CD key is free and Valve doesn't get any money from them. Keys being sold by other stores are also considered retail.

Edit: it wasn't as difficult to find as I though: "Steamworks has a host of features and services that support your retail product and any digital copies, wherever they are sold. It’s free. There is no per-copy activation charge or bandwidth fee."

http://www.steampowered.com/steamworks/retailsupport.php

Holy crap! And people wonder why indie devs want to be on Steam ....

Yeah, I knew that was the case. It's pretty awesome of them and a big reason why everyone without dreams of their own client have gone Steamworks.

I wonder how is that policy working for Valve now. I'm sure that at the beginning it helped them a lot to increase their number of users. Nowadays I can imagine that more than half of the "retail" Steam keys being activated belong to people that already have a Steam account and just decided to avoid the Steam store because of better deals.

Steam is still getting something of the aggravated data. But I don't know if it is enough to pay the bills.

And in the end, digital retail has such high profit margins, that if a customer only buys on Steam for 50$ a year, it might still be a good deal for them.