While it may not meet the formal definition from the buzzword dictionary, I think of BIM like this...
If my software/drawing can give me more than just a piece of paper, that's BIM. If there is a datamodel as well as a graphic model, that's BIM. Or at least has the potential to be.
The whole push for BIM Valhalla (like shown here www.Autodesk.com/PowerofBIM) where everything is some kind of magically interconnected parametric universe is certainly a goal, but it doesn't have to be that complicated.
I would consider the following exercises to be BIM activities:
1- Importing a collection of shp files through the FDO and theming/annotating based on the map data
2- Creating a Material Volume table from a Corridor that pulls information from the combined alignment, profile, and assembly to compile road material quantities.
3- running an elevation analysis on a surface, or labeling a surface, than changing the points and watching the effect ripple through
4- much more in Civil 3D and Map
FWIW the US GSA has an article on the subject that might be considered the "definition" of BIM. The reason a lot of it is hard for us to digest is because it all seems to be written in architectural terms with architectural examples (just like every stinkin' intro to AutoCAD text out there, eh?). If you think of the "Building" as construction in generic terms instead of a _building_ structure, it makes more sense.
http://www.gsa.gov/bim
From the site:
"Critical to successful integration of computer models into project coordination, simulation, and optimization is the inclusion of information—the “I” in BIM—to generate feedback. As a shared knowledge resource, BIM can serve as a reliable basis for decision making and reduce the need for re-gathering or re-formatting information."
Dana Probert
Autodesk