With the announced retirement of Robert Christgau, the self-proclaimed dean of American rock critics, in June, this summer provided the perfect moment for Chicago-based website Pitchfork, a staple of indie music opinion, to expand its mantle, becoming a mainstream tastemaker as well.

But as the upstart site establishes itself further toward the top of critical heap, observers and those in the biz are pondering Pitchfork’s ability to retain the authority of its critical voice — and avoid the appearance of potential conflicts of interest — as it expands into other ventures.

Long known for its king-making abilities in the niche-driven indie rock landscape, the site now exercises widening influence on both record-buyers and Hollywood music supervisors. Indie labels such as Merge and XL scored their first-ever Billboard No. 1s this year, courtesy of Pitchfork discoveries Arcade Fire and Vampire Weekend, respectively, while films “Scott Pilgrim vs. the World,” “Where the Wild Things Are,” “Greenberg” (which featured a score composed by ‘Fork fave and LCD Soundsystem frontman James Murphy) and the “Twilight” series grounded their entire soundtracks around what’s now largely known as the “Pitchfork aesthetic.”

“There’s definitely been a lot of overlap in the last few years between the music that we cover and music that’s been used in film and TV soundtracks,” says Pitchfork founder Ryan Schreiber. “Some of it is a result of people who grew up with independent and alternative music like we did … moving into those worlds, although I’ve also been told by people working in film and TV that they read Pitchfork.”

The site has been making news itself: It tallied massive attendance figures for its three-day namesake festival in July, with all passes selling out within a week (before the full lineup was even announced); expanded into partnerships with the likes of ABC News; spawned lengthy recent Time and New York Times profiles; and racked up an unexpectedly high average of 30 million pageviews per month.

Such success is a far cry from Pitchfork’s modest begin-nings. Started by Schreiber on a single computer in his basement in 1995 and currently operating with minimal core of inhouse staff and a plethora of freelancers, Pitchfork has expanded its brand carefully and skillfully.

The site served as curator for Britain’s All Tomorrow’s Parties festival in 2008 and has since aligned with videogame developer Take-Two to program ingame music. It has also forged unions with indie print rag Fader, promoter Mike Reed for the annual Pitchfork Music Festival in Chicago’s Union Park and, most recently, ABC News for a series of on-camera reviews and recommendations from site editors.

“Pitchfork is the most successful rock journalism startup since Rolling Stone,” says Jim DeRogatis, host of syndicated radio show “Sound Opinions” and longtime music critic for the Chicago Sun-Times. Yet the unavoidable question is whether the site can stand up to the pressures inherent in expanding its brand.

Foremost among those concerns, according to DeRogatis, is the site’s increasingly high-profile concert series and reliance on direct hosting of songs and exclusive video content through its Forkcast and Pitchfork.tv functions.

“There are always questions to be raised about a criticism site organizing a concert, and even more so with a video channel,” DeRogatis says. “It starts to move the site more into the realm of an Internet radio station than a critical organ, and we’ve all seen how radio stations can be, have been and always were susceptible to corruption.”

Pitchfork’s record reviews and elusive “best new music” designations can be the difference between obscurity and notoriety for a budding band. So when the website asks permission to freely host a band’s music, artists’ interest in protecting their own copyright could come into direct conflict with the quest for better press, DeRogatis says.

Schreiber maintains that the annual Pitchfork festival is operated independently of the editorial department and that “while the editors of the site choose the acts that end up on the stage, they have no direct involvement in the booking, production or execution of the event.”

As for the video channel: “All programming is done with the overall goals of Pitchfork as an editorial entity in mind,” Schreiber says. “But those responsible for shooting and securing specific acts, or determining which musicvideos might exist on the site, are different from the people who decide what written content ends up on our site each day.”

Given the site’s small staff, these distinctions can be difficult to gauge from outside.

The site has already been dogged by criticism over its close relationships with the artists it champions, most notably last April, when editors handed singer-songwriter M.I.A. the reins of the Pitchfork Twitter account for an entire day. With no obvious oversight or commentary from site editors, the singer mostly plugged her own clothing line and upcoming record, “Maya,” as well as tweeting long strings of indecipherable word clusters that later turned out to be her own song lyrics.

“What were they saying with this?” asks Christopher Weingarten, Village Voice music critic and occasional Pitchfork antagonist. “The main editorial commentary was, ‘We like M.I.A.’ The not-so-subtle editorial commentary was, ‘And we have access to M.I.A.’ But that’s it.”

Despite the resulting controversy, the incident may have unintentionally provided a barometer of the site’s ability to keep editorial and content relationships at arm’s length: Pitchfork soon after gave “Maya” an unflattering 4.4 rating out of 10, despite the cross-promotion with M.I.A. and advertising from her on the site.

But the tweeting stunt points up a degree of naivete increasingly at odds with the site’s reach.

“Ryan still looks at (the site) like he’s still in his basement trumpeting stuff that he loves,” opines one Chicago-based critic. “But he does have a bit of the empire-builder in him.”

Pitchfork boasts several advantages over its forebears Rolling Stone, Creem and Trouser Press: low overhead, no print costs to cover and an army of freelancers eager to unearth bands beyond the reach of many old-school music publications.

“Aside from the five or six guys who are making a living at this, you still have people here who are doing this from a sense of love, often for nowhere near the compensation that the hours of work ought to allow,” DeRogatis says. “They’re doing this because they love the music, despite all the complications.”