I’ve seen the words “good thing ™” used in a variety of different places, just search for it on google to see. What I’m confused about is why so many people feel the need to put ™ on the end of it, anyone have any ideas from where or why this practice come about?
It’s been trademarked by Martha Stewart and is therefore a subject of much mockery on the Net.
ahh, thanks for the definitive answer 
How in the world Martha Stewart (or anyone else) can trademark for advertising purpose a common, everyday expression, is beyond me.
Andthat’s not a good thing.
For completeness, the Jargon File’s explanation of the term as applied to computers.
Not me, I think it’s an entirely fair and balanced practice.
Martha Steward or her company did own trademarks using the phrase “It’s a good thing”. But as far as I know, all those trademarks (serial numbers 76405239, 74702308, and 74572334) are now listed as “abandoned”. From the records, I get the idea that the owners failed to respond to complaints made to the Patent and Trademark Office.
What about serial number 2272142, which is the page I linked to? It said it’s still live.
Hmm. I see that the page I linked to timed out. So here is the data given there. (It’s not copyrighted, being a government site.)