Stardock estimates "based on discussions with publishers along with the numbers we are aware of" that Steam owns 70% of the digital distribution market, while Impulse sits in second with a 10% share and the remaining 20% is shared between all others.

The successes of Steam and Impulse are due in part, Wardell believes, to their digital exclusives. Impulse's include Sins of a Solar Empire and Demigod--which it publishes--while Steam has the Left 4 Dead and Half-Life developer's own games as well as third-party releases using Steamworks for DRM, among other functions.

Wardell describes Steamworks as a "challenge" for Impulse as it effectively creates Steam exclusives of games which are not technically such.

"Once a game requires Steamworks, it is effectively cut off from us, which limits our content," he explains. "The problem is that it is not practical for us to install a game that in turn requires the installation of a competitor's store and platform in order to play it."

Stardock was one of several digital distributors who recently spoke out against Call of Duty: Modern Warfare 2's use of Steam for DRM and other functions--described by a representative of competitor Direct2Drive as a "Trojan Horse" for the Steam store.

Stardock's "alternative" to Steamworks is Impulse Reactor, a suite which currently offers only basic functions but is intended to become a full-fledged competitor. Impulse Reactor already features players accounts with achievements and rankings, as well as a DRM solution 'Goo' which allows players to transfer ownership of games.

The report explains the next 'phase' of Impulse Reactor will add a player messaging system as well as multiplayer services including anti-cheat, NAT negotiation and persistent servers, making for a platform far more comparable to Valve's Steam.

Wardell admits that community features in its Steam client equivalent--the separate but confusingly similarly-named Impulse--"still lag significantly behind... in some areas."

He explains it needs a "good" in-game overlay system, voice communication option and "way to get people together for discussions, groups, modding, etc"--as found in Steam.

One feature currently in beta not found in Steam is 'Ready to Play,' a tool which allows players to be matched with like-minded players for any game by creating a profile detailing themselves and their idea of "fun" in games.

Wardell estimates that for this year "digital distribution will represent approximately 25% of the revenue for a typical PC game publisher on a new title," with the reasonable disclaimer that "this varies significantly based on demographics."

The question "How do you purchase software?" in Stardock's annual customer survey, while hazy, suggests a sizeable shift. Respondents buying "digitally" is up by roughly half over last year from 42% to 61%, while "in a box" consumers fell from 58% to 34%.