why do people put # in front of a phrase with no spaces at the end of facebook posts?

[Robert Russo]

people will say things on facebook and then end their post with something like "#myawesomelife" and i do not understand what it means

[Josh]

I believe there referring to Twitters hashtags

[Chel*Belle]

Its called a hashtag. Its mostly done on twitter but because facebook is just as popular people just pick up the"trend" so to say. Like mine the other day was like " this guy in my class always matches his shoes to his shirt. #trueswag" I'm saying that this guy has true swag because he knows how to dress well. It's really just pointless and for fun.
Hope that helped