First Lady Michelle Obama officially joined the Twittersphere today, a move meant to expand her influence and outreach for the 2012 presidential campaign.

The account - @MichelleObama - will be managed by President Obama's campaign staff, according to a statement on her profile page.  Tweets directly from Mrs. Obama herself will be signed "-mo."

The first lady, who remains highly popular in public opinion polls, is seen as a significant asset in the effort to re-elect her husband.  On Wednesday, she hosted her first two fundraisers of the year with supporters in Virginia.

"Let me tell you something - I am in.  I am so in," she told an intimate gathering of donors in Charlottesville. "That vision that we know, that world we want to create, we know what it is, but we have to work for it, and we need you fighting, working, hustling every second of the day until election day."

Within the first two hours of launching her Twitter account, Mrs. Obama acquired more than 25,000 new followers. President Obama (@BarackObama) has more than 11.8 million followers and is the third most-followed public figure on Twitter.

UPDATE:  The First Lady sent her first tweet at noon ET.  "Hi, everyone, and thanks for the warm welcome. Look forward to staying in touch with you here. -mo"  Four hours after her account went live, she now has 75,000 followers and counting.