This week, Bill Gates joined Twitter. (In a matter of hours, he had over 100,000 followers.)

Roughly 200 miles above the earth, someone else also was sending a first message to Twitter. NASA astronaut T.J. Creamer posted "Hello Twitterverse!" (surely the 2010 equivalent of "Hello world!") directly to the social networking site from aboard the International Space Station. According to a CNET article, previous astrotweets had to be emailed to ground control, which then posted them.

Other technology-related Twitter accounts include the European Organization for Nuclear Research at @CERN and @LowFlyingRocks, which mentions every object that passes within 0.2AU of Earth. In 2008, the Phoenix Lander posted updates (or, rather, someone at NASA did) about its findings on the surface of Mars to @MarsPhoenix, and NASA has continued to update the feed even after the Phoenix went silent near the end of that year.

And, of course, if you want software experts, some of the best are regular users of Twitter. Check out the Twitter StickyMinds Authors List to find many of the authors from StickyMinds.com and Better Software magazine. (If you've written for StickyMinds and aren't on that list, drop us a note on Twitter and we'll add you.)

If you use Twitter (follow us at @StickyMinds!), who do you follow for software instruction or conversation? Who (or, in some cases, what) do you follow just for fun? Let us know in the comments below!