Personally, I like to keep the editorial content away from the glossy brochure side of the site.
The approach I've tried to consistently use is to have the product/service pages, and relevant details, all on the relatively static side of the site, referred to as the glossy brochure part of the site. Here, the voice is quite corporate, but benefit driven, explains products, what they'll do for people, what they cost, and why they're an ideal choice for a given demographic.
The blog side of the site is great for editorial. Its voice can vary, have multiple authors, go into detail about particular aspects of a product (that would otherwise be too wordy on the glossy brochure side). The blog is good for colourful background, histories, use cases or case studies, and can be targeted much tighter than the glossy side, where you're trying to appeal to the wider audience.
The blog benefits from the Google Fresh algorithm boosts, so that when you post something new, it quickly ranks, and then fades if it isn't good enough to hold its ground. It can link back to key pages on the brochure side, target long tail phrases, and becomes a funnel that pulls traffic in and pushes it to where you want (often CTA's for further down the sales/marketing funnel).
As fisicx said, it doesn't have to be called a blog - it could be a category on the glossy side of the site - really the two are indistinguishable to Google and humans. The key is slotting it in so it doesn't distract from moving people through the sales funnel, making sure it pulls in traffic and then helps direct those prospects where you want them to go.
For us, the blog gets people to download best practice guides, manager guides and occasionally view product demos or trials. Once we've got their details, then it's a series of drip fed emails to nurture them into buyer ready states. This drip nurturing is done using marketing automation software we built for ourselves in-house, though any store bought MA tool could do the same for anyone else. Drip campaigns keep you front of mind. If they're any good, they keep you front of wallet.
As far as social goes, whenever I post on the blog, I mention it socially, getting a backlink, some added page views, and validation to Google. It has a minor SEO benefit, a minor sales impact - but it only takes a couple of minutes, so it's a small expense with a variable return.