what is memory skill?

IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi 
A memory skill is like a TM (technical machine) in Pokemon, it is also contained in a Pokeball. You will use it to teach a new skill among three types (offensive/defensive/support) to your Digimon.
But there s a lot of limitations:
IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi 

1) no jogress can learn those skills,
IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi 

2) only the current form of the Digimon you choosed will learn it (example: you use the item on a rookie: champion and above won't be able to use the skill), and only one memory skill can be teached to the Digimon,
IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi 

3) memory skills are cash shop exclusive (Digimental price),
IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi 

4) you can not choose the skill you want: you must buy the pokeball from the desired category in cashshop then pray to get the skill you want: there are three category, each category has several skills, and each skill three levels... so the probability is low.
IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi 

5) the use of one such skill will obviously cost Digi-Soul from your Digimon, but also some disks items (50 included in the Cash Shop PokeBall). Those items can be bought from some NPC (with Megabytes) or dropped from certain Digimon.
IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi IiIiIi 
If you are interested in the exact available effects, look at this FoxyGamer's review.