This is great news, but I don't expect the entire game industry to embrace Valve's model. Though it would be wonderful if all developers could develop and distribute their games without publishers (who more often than not fuck them over and violate their games in every imaginable way), not all developers have the luxury of being self-sufficient. Valve is apparently rich and successful enough to finance its games from preproduction, through entire development cycle, to distribution. Most independent development teams, particularly younger ones, simply don't have the funds to close the financial scheme and complete the development cycle on their own. For example, Firaxis Games actually managed to distribute Sid Meier's Antietam via Internet, but not before having their first (and possibly most successful) title, Alpha Centauri, published by Electronic Arts.
Unfortunately, by signing contract with a publisher, development houses also inevitably grant them distribution rights, thus flushing any notion of 'independence' down the toilet. I do have hope, however, that given the opportunity, more development houses will switch to self-distribution model. If it proves successful on a mass scale, the industry might become polarized - on one hand there will be corporate giants like EA encapsulating dozens of teams, on the other hand there will be many small teams self-funding development and distribution of their products. Both models will likely involve a lot of risk, the former due to its inert corporate nature and the latter because a developer's ability to make financial ends meet will always depend on commercial success of one or two titles.
