CHARLOTTE -- There's a new speech-maker being heralded at the White House and her name is Michelle Obama.

"I might be a bit biased, but I thought @MichelleObama knocked it out of the park at the convention last night," tweeted President Obama, in a post he signed himself.

The first lady opened the Democratic National Convention on Tuesday night with the message that President Obama understands the middle class and their concerns better than his Republican rival Mitt Romney.

By the time Michelle Obama finished telling stories of the couple's own struggles with money and their shared dreams for their daughters, Twitter had exploded.

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According to the online social networking service, there were 28,003 tweets per minute at the conclusion of Obama's remarks. That's about double the number after Romney's acceptance speech last week, which was 14,289 tweets per minute at its peak.

"She was stunningly powerful, straight from the heart," tweeted actress Ashley Judd, who is a Tennessee delegate to the convention. Judd said Obama was "breathtaking" and that the first lady's remarks left her "rather speechless."

Democratic strategist Donna Brazile, who ran Al Gore's presidential campaign in 2000, posted on Twitter that she thought Obama delivered an "inspirational" speech.

She also noted the reaction inside the Time Warner Cable Arena. "Love is in the air," Brazile said.

The reaction from some conservatives was not as effusive. Syndicated columnist Charles Krauthammer said on Fox News that Obama's speech was "brilliantly delivered" but not convincing.

"I'm sure in the arena it's a plausible story," Krauthammer said about the first lady's description of the effectiveness of her husband's policies. "I thought it's a great speech, but I don't buy a line of it."

Blogger Michelle Malkin mocked in a Twitter post that Obama's line about the president not believing in "us" vs. "them" was "the knee slapper of the night."

But like Ann Romney's well-received speech last week at the Republican National Convention, will the remarks by the candidates' spouses make a difference with voters in November?

Independent analyst Stu Rothenberg, who publishes a political newsletter, says there might not be any impact. "Michelle has become a terrific speaker," Rothenberg said on Twitter. "But why should that matter -- or whether Ann Romney loves her husband -- in picking a president?" "