Oh come on, not again. You know it's not true.
I say prove him wrong with facts. Neither claim may be validated from the data provided so far. You've both an unsubstantiated opinion but that doesn't make either opinion less potentially valid. In my personal opinion saying something is 'not true' without presented evidence is not an honest and fair practice. (Personally, I wouldn't expect Frogboy to make a claim that he couldn't back up with facts)
All that said: Let the data fly! I'd like to see the back-and-forth on this draw to a peaceful close. 
Impulse has been released in June 2008.
Stardock isn't new to selling games or selling bundles / offering discounts to loyal customers. Flat-rate discounts are a semi-new trend though (from what I can pull from archive.org and ignoring pre-orders/bundles), you're right, but Stardock has been in the business of selling games for far longer than Steam has. Given the lack of raw data anyone has presented thus far about the subject (forgiving information available off Stardock's site regarding), I did a little sleuthing of my own and came up with the following:
The evolution of sales and discounts procedures for Stardock Software, according to their Products page (pulled from Archive.org):
Services provided:
Stardock Entertainment (2000)
Drengin.net (2001-2003)
TotalGaming.net (2004-2007(?))
Impulse: (2008+)
Evolution of sales offers and customer incentives
2001: "You can purchase these games individually or all together by joining Drengin.net (in which you get everything we make for a year after it goes 1.0)."
2004: "You can purchase these games individually or all together by joining Drengin.net (in which you get everything we make 12 months after your order)."
2004: "For a single fee you get all the games already on it plus everything that is added onto it for a year."
2005: "[...]or become a TotalGaming.net member and buy them at a discount using our unique token system."
2006: (First Bundled Game): "PowerGamer 2006 combines several award winning, strategy games together into one exciting package. Games include Galactic Civilizations, Galactic Civilizations: Alterian Prophecy, The Corporate Machine, The Political Machine." (Also a price reduction on TotalGaming.net from the $70 range to the $60 range)
2006: (First Pre-Order) [GalCiv 2: DA for $24.99 ($5 off)]
2007: (Token prices are now listed next to the prices of games)
Addendum
I would list the changes seen in 2008 before and after Steam's release and the last of '07 but they switched over to a more complex interface which broke Archive.org's site crawler. Sorry.
Frogboy, if you've got some behind-the-scenes data that's not publically accessible through Wayback and such (like if/when you sent out discounts to newsletter subscribers and etc) I think data like that would expedite this recurring argument to a peaceful end.
Thats why total sales/revenue per year would be very usefull for comparison of DD services.
Back on target (whew!) I'm also interested in something like this. The NPD tracks console sales and though they're not really "accurate" they're a window we can gaze through at least and that's better than nothing. If someone were to legitimately measure from POS where digital downloads were going and what incentives best engage customers to buy products, I think we could start seeing some interesting trends to capitalize on (like how significant a gain of market share would you get from going from $50 to say $20? Enough to justify the drop in price for a AAA title? How does it affect indie titles?)
Of course, spoiler, I'm a marketer and a developer at a small indie studio so of course I'd like to see more data from original sources. 
