I was asked by the Chartered Institute of Marketing (CIM) recently to put together a small piece on digital PR, the result appears on the What's New in Marketing website (a joint venture between the CIM and search company MediaCo among others).
I found writing it quite a useful excercise, having observed online PR evolve over the last the last couple of years. It helped me to put all this stuff into perspective. I'm sure on a tactical level techniques will always be developing, but there is a need for an overview - useful for those who have yet to step beyond traditional PR and also for experienced digital PR professionals who just want a sanity check.
Perhaps I should expand it and add it to our whitepaper series.