With ironic, or not, reference to the rhetorical skills and intellectual abilities of Barrack Obama, a person who boasts about their ideas and accomplishments. Depending on the context, the term is used ironically to contrast the "oboomer" with Obama, or to suggest that Obama is himself an "oboomer."
Bob never stops yapping about the great things he has done, and and is going to do. He thinks he is soooo smart.
Yeah, he's a real oboomer.
While our lifespan is the number of years we will live, our healthspan is the number of healthy years we will have and our sexspan is is the number of years we will continue to be healthy enough to continue having an active sex life.
A lighthearted reaction upon receiving disappointing news of some sort. Usually something that isn't a particularly a big deal, esp. when it primarily affects someone else - sort of a mild schadenfreude. Sometimes doubled or tripled, and possibly said in a sing-songy voice for added comedic effect to imitate a muted trumpet, which is how the meme originated.