Since last fall my 16-year old site has gradually lost about 75-80% of its pre-Panda traffic and, commensurately, revenue. It wasn't pandalized or penguin-ized per se but rather was just bumped down in the SERPS from #1 for several 3- and 4-word phrases to a lower position on page 1 of Google's SERPs. My hunch is that, as it stands, the site will continue to languish and perhaps fade over the coming years.
This is a static, informational site in a clearly defined niche for an evergreen demographic on an evergreen topic. A simple blog that provides weekly (or even daily) news and events related to the site's topics would be easy enough to implement and maintain. (But I don't want to get into forums or even allowing post comments -- too many pitfalls and risks as far as I'm concerned. And no tweeting of Facebooking for me, thank you very much.)
What I would like to know is if anyone here has simply added a blog to their languishing site and boosted their traffic significantly as a result. What I would be hoping for would be that my frequent blog posts would be picked up by the search engines and put up on page 1 of the SERPs for at least a few hours, if not a day or so. And hopefully more visitors would bookmark the site and return regularly for blog updates, further increasing my traffic. Is this just wishful thinking, or would it be worth my while?