Twitter hash tagging?

[johndoe7]

So i am having some difficulty understanding the concept behind "hash tagging." I have gotten into countless fights with a friend of mine over it. To me hash tagging is nothing more than a way to highlight something in your tweet to make apparent, however, my friend claims that tweets can look "immature" and one can look confused with twitter if they dont hash tag a general topic that other people have hash tagged before. Personally, i find twitter to be nothing more than a social media site where one can just write stupid pointless or silly things just to try to be funny, but can tweets with more specific hash tags, maybe relating to more of an inside joke or something that only few followers would understand really be considered immature? Is twitter not just a way to simply express something on your mind, whether it be funny or stupid or whatever? And finally, is hash tagging truly something that can be done "wrong" ????

[joko]

isnt it just to aid peoples searches?

if you have nothing worth searching no need for a tag