Writing a blog is no way different from writing for a magazine. When many people send their writings for publication in a magazine the editor selects the best of lot and they are published and circulated and read by so many readers.
Same thing is happening in the world of blogging. It is a virtual world where we are submitting our writings through our blog and depending upon the visits to it some people will read it. If it is very good, people will come again and again and more people will join the fray.
So basically a blog requires two main things for its success - presentation and content.
The presentation part consists of language, sequencing, placement of articles in their proper places, place for comments and feedback etc.
Content is more important as it is the main attraction force. People come to net only for two reasons either to entertain with idle surfing or to search a requisite data. If they get their item of choice they will remember your blog for a long time and will keep it in their favourute list.
Thoughts exchanged is knowledge gained.