How many observational techniques are there?

I am currently researching an article for a leading market research magazine on the topic of observational/passive research. My first task to scope the project by defining all the different approaches, I will then be looking at which are (or should be) within the remit of market research and which should remain outside our domain.

At the moment my thoughts are that the following are all important aspects of observational/passive research:

1. Blog mining. From Technorati, to twitscoop, to sophisticated approaches such as BuzzMetrics allow us to listen to the conversations that are happening on the web.
2. Web Stats/Metrics/Analytics. From specific products such as SpeedTrap to the almost ubiquitous Google Analytics systems are producing a wealth of information about visitors to web sites. Increasingly market researchers are being asked to linked this browsing behaviour to the results of visitor surveys.
3. BT (Behavioural Targeting). BT is increasingly being used by advertisers and is beginning to elicit concerns from citizen groups and legislators. BT uses a combination of browsing activity, responses to fields (such search requests and queries), and potentially the content of messages to determine what service or advert to promote to the user.
4. Video Tracking. More and more video cameras track our every movement, along the street, through the mall, around the store, and even through many workplaces. What commercial use can and is being made of these?
5. Loyalty Cards. Whilst loyalty cards can deliver customers discounts, they deliver to the operator information about what is bought when, by whom, in association with what other products, with what frequency. By combining this data with survey data the operator can build models of possible triggers for future marketing.
6. RFIDs. Radio Frequency Identifiers are being built into an increasing wide range of products. They have been put into shopping trolleys (carts) to map the behaviour of shoppers, and they have been put into high value products to alert retail staff to the arrival of a high spender.
7. Mobile phone tracking. Researchers have been tracking the flow of people through retail malls and of card through cities by tracking mobile phone signals. With the rise of services like Google Latitude we can all start tracking people, is this a opening for market researchers?
8. Paradata (invisible processing). When people complete a survey online we often collect more than their responses. For example, we might collect when they started and finished the survey, how long they took on each page, what sort of connection speed they were using, what sized screen they had, and details about the operating system, the location etc. To what extent are respondents aware of this, to what extent should they be aware (especially when we are using it to detect cheats)?

I have specifically excluded the observational techniques that require the express and unambiguous consent of the subject, such as in-home ethnography and accompanied shopping as it seems to me that the ethical and practical issues surrounding these activities are better understood, and most of us are quite clear that these sorts of observational techniques are a proper part of market research.

What are your thoughts?

Does anybody have a better collective term for these approaches, other than observational or passive research?