-To communicate to the world about the way you feel about politics, religion, science, etc. It's pretty important.
-To communicate to other individuals, who are interested in hearing your musings.
-To communicate to yourself. Writing is (in my opinion) the best way to find out things about yourself.
That's my best effort.

fair enough.
So I'll blog today, then:)

[untill this question again arises, and untill I again feel like not-blogging-forever]