The social networking site can create a widespread buzz for low-budget films like ''District 9''

By Nicole Sperling
Updated July 31, 2009 at 04:00 AM EDT

Twitter giveth, and Twitter taketh away. The social-networking site — which links users (yes, you, John Mayer) via 140-character mini-blog posts — has already been blamed for hastening the demise of Brüno, which opened on a Friday to $14.4 million and sank like a stone the next day. Now marketers are trying to use the texting site to their advantage. On the first night of Comic-Con, Sony Pictures stacked an audience with movie bloggers and screened the low-budget, R-rated sci-fi flick District 9. By 11:39 that night, audience members’ Twitter raves had reached American Idol winner Jordin Sparks, who posted ”Omg I Want to See District 9 asap” to her 220,000-plus followers. A Web sensation was born.

Will that buzz turn into box office? We’ll know when the movie opens Aug. 14. Until then, Twitter lets execs — like Sony’s marketing co-president Marc Weinstock — know instantly whether their efforts are working: ”It’s lightning-quick feedback.”