Presidential debates are customarily scored and picked apart the instant the moderator says “good night” at 10:30 p.m. But the Web is speeding up time. When the first of this season’s debates started on Wednesday in Denver, the scoring began at 9:01 p.m., as soon as Jim Lehrer, the moderator, said “Good evening.”

Mr. Lehrer’s open-ended questions, Mitt Romney’s plan to end the federal subsidy for PBS and Mr. Romney’s high energy level — against President Obama’s comparatively low energy level — all received spikes of attention from viewers who were chatting online along with the debate. The instant feedback helped harden conventional wisdom that Mr. Obama had turned in a weak performance, even before he had finished speaking.

On MSNBC, liberal hosts like Ed Schultz were taken aback by Mr. Obama. Mr. Schultz threw up his arms at one point after the debate and asked, “Where was the president tonight?”