For a general definition of blogging: You should be asking for help on puzzling problems. You should be tagging your best pictures on flickr. You should be getting recognition for your genius and hard work, as well as business, money, priceless feedback, and readers who one day may become friends. You should be sharing the things you learned so other people will learn from them and maybe teach you something new. You should be entertaining the rest of us; and we will return the favor.
Here, your audience is unbounded in space and time. Yes, your writing will last forever — get used to it.