Often times, I have card sets that have a certain ability. However, often times I found the card runs out of room when I type out a description for an ability. That's why we give it a keyword! For example, I have an ability I have added to some of my creatures:
1) Whenever a creature takes or deals damage, it gains that many Ultimate counters, up to 100.
2) At any time on your turn, you can remove 100 Ultimate counters. If you do, do N.
If you've ever had trouble with extremely long abilities for your sets, this would be a brilliant solution. What do you think?