Information from personal blogs only has the authority of the blogger. Before you
could use such material for academic support, you would need to establish the
academic credibility of the blogger, and your citation would need to justify the
validity of the source. If the blogger has academic credibility, you will almost always
be able to find an academic source for the material, and should use that in
preference. Of course, if you are using such information as evidence of popular or
public or personal opinion, that is different.