Make sure you cut-and-paste the entry, it will truncate if you type in the field. Yes, you should do it, but don't agonize over it all. It's just what they say : anything else you want them to know that would get you in? Want to elaborate on your work ethic, diversity, personal goals, community service? That's where it goes. Both S1 and S2 wrote 200 words, that was the old word limit. Your common app essay is likely overly long, but a good place to start.