When I started blogging (that is, reading other blogs too) I had a very different mindset about the game. I wanted comped tournaments and battlepoints at some point, believe it or not. By reading some excellent articles in blogs such as 3++, BoV, The Back40k and others, it helped me shape a totally different opinion. Competitive 40k stopped being such a mystery to me and all the little pieces fell into place. The blogsphere is also a great place for finding hobby articles (such as for converting and painting) so I would definitely recommend for everyone to delve into it.
So, yeah, my point of view for many 40K related subjects changed though the blogging experience. So did the content of my blog. I was originally intending to just post pictures of my painted stuff. I am not the most diligent painter out there though so that would amount to a couple of posts per month. Not a very good way for people to find you out and started reading your stuff. So I started to write about my second favorite aspect of the hobby. Playing. I started with some battle reports since I figured out you don't have to be an expert to write one up. Then I even did some of my own tactics (gasp!) articles. Not sure if they helped anyone out there but I hope they did.
My point is that blogging made me rethink a lot about 40k and helped me push my ideas and tactics further on. And that must be a good thing right? Nothing good ever came out of stability, it's change that pushes us forward. So I hope I will be blogging and evolving for the following 12 months to come. Amen to that.