I suppose the UK market hasn't properly got to the stage of understanding blogging for SEO just yet. I'm not sure where it's at over there but across the water here it is becoming a huge tool to get ranked for medium to low competitive search terms for small business websites, particularly around the trade service industry. Every fucking plumber is starting to write blogs and seeing their ranking increase.
It's just as big over here, and like everywhere else its used by people thinking all you do is write some articles, post them up, share them to your social networks (no good if you're a start up or have a low following as a small business) and then that will get you rankings. Yeah having some additional content on your site will help with Google as it will show you're a thought leader in your niche (if they are well written, original posts, which Google can determine!), it'll also show your site is updated regularly to them.
However the real reason for blog posts and content marketing along those lines (info graphics, videos, memes, etc all hosting on your own site) is to use out reach to increase the spread of this content, and gain links back to it. If you do your out reach correctly then the types of links will be relevant to your site and will therefore indicate to Google your content is good and trusted and therefore your site should be further up the rankings.
Of course this often gets abused with sites gaining links from random and dodgy sources, but Google is well onto this now and it'll only end up in a site penalty (I've cleaned up multiple sites with shite link profiles from doing this).
That's why it's really no longer something which will easily gain you rankings unless you're dedicating the time to write great articles on a regular basis, build the relationships with influencers in your niche who will actively work to share your content, follow up on successful articles and look into least successful ones, etc.
