One of my colleagues was trying to measure blogs (how many, how often, etc.) and i warned her that she…

Metaphorically, it does capture some of the idea of the different aspects of blogs. The mapping doesn’t have to be too strict either: many common protocol stacks (particularly ones with TCP/IP in the middle) don’t map especially cleanly onto OSI.

Just as a quick suggestion, level 7 (application) could map onto the ‘what blogs are about’ element you discussed earlier.

Level 6 (presentation) could, approximately, map onto the traditional blog format.

Level 5 (session) could be the blogging software, such as Movable Type or whatever.

After this, things start getting blurry.

Arguably, from a software point of view, this is mostly nonsense. Blogging software is all at levels 6, 7, and above: level 6 is really intended for things like file formats, encryption and so on (eg XHTML and RSS); and level 7 defines application specific APIs (in this case things like an ‘add post to blog’ command). Everything else is outside the scope of software. As Claude Shannon said in 1949, “Frequently the messages have meaning, that is they refer to or are correlated according to some system with certain physical or conceptual entities. These considerations are irrelevant to the engineering problem.”

That said, I still think it has a certain suggestive power, and might be worth thinking about more.

All this brings me to ask a question: Do Habermass et al draw distinctions between the mechanisms of communication (‘he spoke English’); the experiece of communicating by particular means (‘he liked the sound of his own voice’); and the meaning of given communications (‘he discussed the eschatology of Buffy’)?