There’s an excellent fansite for this movie with a lot of invaluable research called Outpost 31. You can find some very thorough discussion of the movie, a timeline of the major events, and a frequently asked questions which goes over a lot of the mythology of the events in the film.
Producer Stuart Cohen wrote a series of blog posts at the start of this decade, which gives a timeline of the events surrounding the first half of shooting and Carpenter’s extensive rewrites to the script, among many other things including casting and budget.
Jonathan Rosenbaum’s blog details his set visit in December 1981.
Joe Valdez has written a great piece called “Is this the most-hated film of all-time?” at This Distracted Globe. It runs through the production, release and reception of the movie very well.
Anne Bilson wrote an excellent retrospective on the film in 2009, prior to the release of the prequel, for The Guardian.
There’s a lot of places on the web that hotly debate the ending of the movie. Some of the betters ones are listed here.
For a different perspective, writer Peter Watts wrote a short story “The Things” for Clarkesworld Magazine. It was nominated for or a finalist for the 2011 Hugo Awards, 2010 BSFA Awards, 2011 Locus Award for Best Short Story, and 2011 Theodore Sturgeon Award. It won the 2010 Shirley Jackson Award. It’s a story written from the viewpoint of the Thing itself and is available in its entirety on the Clarkesworld website.
If you want to follow us on Letterboxd as well, we’re always logging and rating films we’ve been watching and occasionally Luke will do some pretty in-depth reviews, too.
Luke Kane: http://www.letterboxd.com/overbreakfast/
Cameron Crothers: http://www.letterboxd.com/crot00192/
Damien Heath: http://www.letterboxd.com/jedikaos/
Luke also wrote an in-depth review of the film in June 2014 on his Letterbox account.