blog vs microblog

blog and microblog both are nouns.

Word	Noun	Adjective	Verb	Adverb
blog	Yes	No	Yes	No
microblog	Yes	No	No	No

As nouns, microblog is a hyponym of blog; that is, microblog is a word with a more specific, narrower meaning than blog:

blog: a shared on-line journal where people can post diary entries about their personal experiences and hobbies
microblog: a blog in which there is a limitation on the length of individual postings.

blog (noun)	microblog (noun)
a shared on-line journal where people can post diary entries about their personal experiences and hobbies	a blog in which there is a limitation on the length of individual postings.

blog (verb)	microblog (verb)
read, write, or edit a shared on-line journal