This is a wonderful initiative! A comment: Sorting a very large list with little RAM is not necessarily a problem! Try:
mkdir tmp
cat unsorted.txt | sort -u -S 65% -T tmp > sorted.txt
rm -r tmp
-S will tell your machine to use at most 65% CPU; this is some sort of optimum, according to my experience
-T puts temporary files in a directory (here named "tmp") and not in RAM; if you have an SSD, the speed isn't too shabby
I have sorted huge lists (>80 GB) on budget laptops using these two arguments. Worth a show! If you want better hosting, PM me.