The word blog is "online journal." That was the beginning. Now, a blog can be anything: Blog Review Blog jokes, "what I did today ', online store, news site, photoblog, etc..
Each man can make a blog or a hundred. And everyone can do what he wants, as long as a follow common sense rules. I chose to go on recess, said improper 'niche' opinion. So Blog opinion.
Expressing opinion is the guarantee of Freedom. Generalist and treated subjects, where I more or less a vague idea about the subject, normally I will not get to write about quantum physics.
There are people who consider that not everyone is entitled to an opinion. Is it? Does it qualify as a somebody have this right? Faculty, bank account, noble, IQ, gender, race, religion, age, .. what?
Better. I write today about a rally. One certain, fictional say. And I give their opinion about it. Someone my attention that it is normal to express my opinion. If I would have pointed out that wrong in approaching the subject, do not know all the facts that are subjective, the "n" factor, I would appreciate it. It means that man has read, understood, and then he offered insights.
But no. I'm not allowed. Yet, who also commented on the edge of a subject makes expressing his opinion. For, the moment when he says that I do not have this right, he makes this statement based on his own opinions. So by logic itself, or it should not have an opinion.