Mrs. Obama was a regular reader of Lisa's organic gardening blog, where she posted encouraging comments under the username "FLOTUS1." When Lisa's school mates ostracized her for being an overachiever, Lisa wrote about it in her blog. Mrs. Obama came to Lisa's defense, arriving at the Springfield Elementary School playground in a helicopter with Marines and Secret Service agents. She gave a speech to the students about the importance of academics, encouraging them to be nice to the overachievers at the school, specifically Lisa, Martin Prince, and Allison Taylor. At that time, Mrs. Obama also told Lisa that she read her blog, and that she was the commenter FLOTUS1.
FLOTUS1 is an acronym for First Lady Of The United States One. Mrs. Obama said she would have used FLOTUS as a username for posting comments on Lisa's blog, but it was already taken by Ralph Wiggum, who said that he "[swam] with his flotuses on."
Despite Obama being First Lady of the United States at the time, she didn't voice herself, and was instead voiced by Angela Bassett.