You raise good points Dave, and I think that all the questions you are asking are valid ones. One can speculate a lot on what is happening on a daily basis in the SERP, on the official posts google is releasing or on the patents they are filing. And speculations are healthy, when they lead to actions though:

1) trying to formulate a theory about what impact onsite and offsite triggers have in the Google ranking algorithm.
2) set up a benchmark in order to demonstrate the theory.
3) provide solid data proving that the theory is sound, and that particular conditions lead to consistent and predictable results.

Once step1-3 are complete, one can then put the theory forward with confidence and advise other people to follow it. But without a proven theory, I believe that it is always safer to play by Google's rules, as described on their (un)official blogs.

One thing is for sure, people such as Activeco can benefit greatly from this type of speculations - my blog is also open for testing: http://galide.jazar.co.uk. Please throw as many links as you want at it and see if we can to take it down

Manu