I don't even know what Facebook Paper is and don't care. However as you mentioned, compounds, even of the simplest kind, are a GREAT idea. The important thing is that, even if you lack the common sense or creativity, it is completely and fully unreasonable to not expect someone else to make the same bad decision. Open letters, heartfelt emotional addresses and displays of surprise are not a thing that should happen and instead, if one feels the need to go ahead and use one of the top 300 english words, one should be fully prepared for legal battles ahead.

In short: Hire a gaggle of lawyers before using any of these verbatim: http://simple.wiktionary.org/wiki/Wiktionary:Most_frequent_1...