When talking about conversion rate it’s important to define what exactly you’re converting.
If you’re talking about converting visitors into customers, then yes, content can increase your conversion rate.
If your website just sits there and your visitors can’t engage, chances aren’t that high that they will make themselves known to you.
However, offer a piece of engaging content in exchange for a name and an email address, chances are suddenly much higher that they will engage.
If you can subsequently nurture that “known” prospect into a customer, then you generated a customer through your website. Where you would otherwise have missed out on that business.
At Net-Results (where we compete with industry giants such as Marketo and Pardot) we’ve seen considerable success with visitors engaging with our content and subsequently becoming customers. Despite people saying that people don’t want to fill out forms anymore… well, they still do. 🙂