It's been a big week for social networking.
First, President Obama sent his first Twitter message on Monday. And now Bill Gates, philanthropist and former chairman of Microsoft , has joined the microblogging site, sending out his first tweet Tuesday.
"Hello World," twittered Gates. "Hard at work on my foundation letter - publishing on 1/25."
Since that first tweet Tuesday afternoon, Gates has twittered four more times and quickly amassed a following of more than 188,600 people. He's also made it onto more than 6,000 Twitter lists.
"I've got a lot to learn about Twitter but look forward to sharing more," he wrote Tuesday night.
And when Gates decides to get into social networking, he dives right in.
After publicly saying last summer that being on Facebook was more trouble than it was worth, he quit the site. Well, Tuesday he was back on Facebook with a new page. To avoid being crushed with friend requests this time around, Gates has opted to let people become "fans" of his page instead.
So far, on Facebook, Gates has posted pictures of his trips to Africa and India, as well as information about his philanthropic organization, The Bill and Melinda Gates Foundation.
After a day back on Facebook, he has more than 50,000 fans.
Meanwhile, the presidential tweet didn't go up on the @barackobama Twitter account, which is handled by a ghost Twitterer. Obama's first message, which was about the president and first lady visiting the Red Cross' disaster operation center in Washington, was posted on the @redcross page.
The tweet itself was in the third person: "President Obama and the First Lady are here visiting our disaster operation center right now."
It appears that someone else may have written the tweet, then the president pushed the "update" button to send it out. The next tweet on the @redcross page was: "President Obama pushed the button on the last tweet. It was his first ever tweet!"
Sharon Gaudin covers the Internet and Web 2.0, emerging technologies, and desktop and laptop chips for Computerworld . Follow Sharon on Twitter at @sgaudin or send e-mail to email@example.com.