Christy,
Interesting that you would ask.
The main series of lessons in the ASL University Curriculum are based on research I did into what are the most common concepts used in everyday communication.  I compiled lists of concepts from concordance research that was based on a language database (corpus) of hundreds of thousands of language samples.  Then I took the concepts that appeared the most frequently and translated those concepts into their equivalent ASL counterparts and included them in the lessons moving from most frequently used to less frequently used.
Thus, going through the lessons sequentially starting with lesson 1 allows you to reach communicative competence very quickly--and it is based on second language acquisition research (mixed with a couple decades of real world teaching experience).
Cordially,
Dr. Bill

p.s. Another very real and important part of the Lifeprint ASL curriculum project is that of being able to use the "magic" of the internet to provide a high quality curriculum to those who need it the most but are usually least able to afford it.

(That picture sums up my philosophy regarding curriculum. Students shouldn't have to pay outrageous amounts of money just to learn sign language.  -Dr. Bill)