An absolute and resounding Yes. Every time you remove friction from the flow, your user experience is enhanced. Thus, if your content requires the user to be signed and you facilitate that process, then you're doing things right.
Think about how many people will leave your site because they don't want to follow a signup process, filling forms and such, and how many people will get to your site and actually interact with it because... they are already signed!
This is something me and my team do a lot, and both engagement, CTR and bouncing ratios are greatly improved every time we do it (as a matter of fact I implemented it just yesterday in one site, go figure). But just in case, take a read to http://www.nngroup.com/articles/login-walls/ to a more general view.
This answer has justy one caveat: this approach is good for general purpose sites. And while some sites using sensitive information use this approach (somehow), I'm not fully convinced, so if you need financial info or stuff like that, go with a better non-automated flow that doesn't make teh user think you actually know more about him than what you should (which in financial and sensitive apps is... nothing)