Little is known about them, except that they were a member of the "Alliance of Four Great Races", along with the Alterans, Asgard, and Nox. However, occasional artifacts attributed to the Furlings have been identified. Furling writing has also been seen on Heliopolis along with the writings of the other great races.
It has also been suggested that they are a peaceful race. It was discovered that the Furlings had set up a Utopian community for themselves and any humans who wished to join them, without weapons or advanced technology. The colony was destroyed by a Goa'uld who was able to smuggle in seeds for a plant that produced a paranoia-inducing chemical, causing the inhabitants to go insane and kill each other (and the Goa'uld responsible).
The Furlings appeared to be the mysterious race that helped seed the Madronans on their homeworld and possibly suggests that the Touchstone was Furling technology.