It is used as a "filler". It doesn't usually mean anything. It's just something to say while the person thinks of the next words.
You will also hear "like" a lot.
"Oh that movie? It's was kind of like ... you know ... boring ..."
Other similar phrases are: ya know, ya know what I mean?, ummm, uhhhh, look, it's kinda like, sort of, yeah nah. (They all mean NOTHING) :)