Are hashtags *sometimes* intellectual property?

http://www.business.com/legal/are-hashtags-intellectual-property/

For instance our registered trademark “How hard can IT be?” is used everyday online at twitter:

https://twitter.com/search?q=%23howhardcanitbe&src=typd

There are several questions, but mainly: Do we need to assert some sort of control?

According to the article cited above, probably not — because our Registered Trademark doesn’t “Cite a specific business identity.”

Which is weird because Nike protects “#JustDoIT”

We’re confused. Appreciate any thoughts …