When Pittsburgh Irish & Classical Theatre announced this week that it would stream its Aug. 15 performance of The History Boys live online, the first thing I thought of was a conversation I had with some friends recently. We were discussing why stage plays documented on film or video always feel -- no matter how good the show -- strangely unsatisfactory. 

We weren't talking about the film versions of plays: History Boys, by Alan Bennett, for instance, followed its award-winning stage run with a fine screen adaptation. But live stage shows captured on film are different than stage plays adapted for film. The latter might be talky, but they are created with the camera first in mind. The former are staged for a live audience, sitting and breathing a stone's throw away. The camera merely records what the performers are doing.

Anyone who's ever been disappointed by a concert film, for instance, knows what I mean. The camera can get you closer than even the top-priced ticket, but the performance styles and other aspects of stagecraft account for the person in the back row more than they regard the homebody with the slickest flatscreen. The intimacy is missing; you feel like you're eavesdropping, not like you're part of an event.

PICT's Live and In Person and Live and Online initiative also faces this challenge, I'm guessing. LIPLO grows out of PICT cofounder Stephanie Riso's Cabaret Pittsburgh series, and was developed with Alex Geis, of 21 Productions. In 2007 and 2008, selected performances were fed live to the Web. Riso deemed the experiment a technical success. Not having been advertised heavily, LIPLO didn't have many viewers, but "[t]he viewers that we had loved it," Riso told me today. One cabaret enthusiast accessed the Cabaret Pittsburgh site from Germany.

For History Boys, PICT's archival videographer, Randy Griffith, will capture the performance as he always does: with a single camera positioned in the orchestra pit, one he can pan and zoom for closeups.

But the differences between streaming a cabaret performance and doing so with a full stage production -- one with 13 actors -- are obvious. Cabaret is by nature intimate: One performer, or perhaps a singer and accompanist, speak directly to an audience no nearer to or further from hand than a discreet video camera might be. Stage actors, by contrast, are blocked for audience viewing but play off of each other -- and in character, to boot.

Live performance being more compelling than click-throughs, Riso says LIPLO might help PICT lure advertisers to www.picttheatre.org. It's good news, too, for theater fans who are laid up ill or out of town.

But I have to wonder whether, rather than reaching out to an online audience, the project won't merely emphasize the differences between the mediums -- between shows you're meant to attend and ones you simply watch on a monitor.

Still, if anyone can pull this off, it's PICT, which is among the city's most accomplished troupes. See for yourself: After History Boys, PICT has gotten playwrights and unions to also agree to live streaming of its next two shows, Crime and Punishment, in September, and Jane Eyre, in December.