microblog vs web log

microblog and web log both are nouns.

Word	Noun	Adjective	Verb	Adverb
microblog	Yes	No	No	No
web log	Yes	No	No	No

As nouns, web log is a hypernym of microblog; that is, web log is a word with a broader meaning than microblog:

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

Other hypernyms of microblog include blog.

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