Press Releases can be used to boost organic rankings, and it’s quite easy to understand how this works in principle, but how to measure the effect? And are there other benefits as well. The following articles tries to look under the hood. 
The benefits of SEO tuned press release distribution v2
Search Engine optimization for B-2-B industrial marketing can be quite different than for B-2-C. Here’s some search engine marketing use cases and tips on how to maximize your investment. Optimize your search budget
A bit disappointing to read the MarketingProfs 2009 success story case study collection about Social Media ROI. The paper talks about how 11 known brands that are listening, engaging and measuring social media. I think this part are OK, and there actually some interesting approaches that one could learn from. The connection ROI however is in most cases not there. A statement like “thanks in part to increase coverage (PR) sales have continued to risen….” simply doesn’t cut it, and marketeers need to make sure we don’t claim or take credit for things that we can’t prove. It will only get us in more trouble and not advance the credibility of marketing. On the other hand the story is re-assuring for companies only now starting the experiment with social media, in the sense that not many, if any, have figured out the financial return.