Alexsms....okay, from my teenager's point of view... "Hey there" (and not Hi there) is more when you are talking to one person directly and "Hey" is when you are talking to a group of people. Now me being an old timer, I learned the phrase from the old Mickey Mouse Club intro (on reruns, I'm not THAT old). You can use Hi there, Hi, Hey or Hey there, whichever you like, there is NOTHING wrong with any of them. HOWEVER... when I am writing, I will to put the person's name if I am using only the "Hey" or "Hi" but if I am speaking, I might leave out the name. If I am using Hey there or Hi there, I don't always use the name when writing.