Yeah, a search containing "carpet" brought up 20 pages of threads.
To your question, as JP mentioned I (along with a number of others) use Folex. I only use it as a spotter for things that don't "come out in the wash"

I have tweaked my carpet cleaning process over the years and yesterday spent the day at a training seminar on carpet and upholstery cleaning which gave me some additional information to ponder.
But a basic carpet cleaing process:
*** Disclaimer *** There are numerous variables to be considered, a) how dirty the carpet is, b) the physical construction of the material (natural/synthetic/blend) c) the tools you have at your disposal.
Note, I do not own a carpet extractor. If you do, obviously you will modify the steps accordingly
O Vacuum - Use the best vacuum you can afford. Use as many tools as needed to get into all the areas.
O Vacuum again - Yes, beat the carpet with one hand (or brush) and follow along with your nozzle. This is the most important step to cleaning carpets.
O Pre-spray the entire area using a traffic lane cleaner (TLC) using a pump up sprayer or spray bottle
O Agitate - Work the pre-spray into the carpet - I use a nylon bristle brush
O Allow the product to dwell, but don't allow it to dry.
O Spray hot water (120o or (preferably) hotter - I think 150-160 is a pretty good target temp)
O Extract - You will at a minimum require a good wet/dry vac for this.
O Spray again with hot water and extract
Depending on how dirty the carpets are you may need addtional steps such as:
O Spot treatment
O General shampooing - Use a carpet specific shampoo, again using hot water. I like to really foam up my bucket, using my carpet brush, and then scoop out the actual foam so as not to overwet the carpet. It is a
quasi "dry clean" method.
O Rinse (hot water) and extract - Repeat
Like the vacuuming step, rinsing and removing all soap residues is key to the process. The single best product I've added to my carpet/upholstery cleaning arsenal is a good All-Fiber Rinse. It neutralizes the soap and also seems to help realease any remaining residue. You would use that product as your final rinse.
Go over and over again with your "extractor" to remove as much moisture as possible. Finally, give the carpets a light buffing with terry towels. Allow the carpets to dry. There are several options to facilitate the drying.