Why blog?

I am finally getting my act together (I hope) and writing a blog.
I've tried numerous times over the years to keep a diary but have never succeeded. The furthest I've gotten is one entry a week if I remember correctly.
Everything I want to do in life is often cut short by something else I would like to do. I can't finish anything because I'm over eager to get to the next. Sounds like a workaholic I know but if you know me well enough you'll know that's not the case.
The problem I think is that I never have a purpose in mind when I start writing. The next day I would read over what I had written and feel embarrassed. Not at the content but at the meaningless of it as a whole. So I would scrunch up my diary entry and commit to starting again- eventually.
I feel less bound to my writing now. Writing nonsense is part of writing better and the more I write the easier I'll find it (perhaps) to portray meaning and purpose. And consider if I have been wrong all my life- consider if the endless contemplations I write out are actually worth a read to someone else, in which case it's a waste to throw them away.
So if you find yourself reading over my entries, wondering what the hell I'm blabbing on about, be patient. I am a 20 year old journalism student with a passion for writing yet I have no proof that I've ever written anything at all. I've never been happy with my thoughts once they are on paper so I throw them away.
Now I'm committed to not deleting anything once I've posted it on this site. For this reason, although you may find some of the entries I write pointless, they will nevertheless be on display, so I can learn from my mistakes, improve my writing skills, expand my experience and keep a record of my life.