Every now and then I hear people talking about "modeling data" and usually it doesn't make any sense. Whereas there are some activities that can be called so, I'd bet when You say either of "modeling data", "data modeling", or "data model" you actually mean modeling real-world processes as or with the use of data. The distinction could be the key to the question: what's so much wrong with modern software?
Here I propose two definitions. They're both debatable.
Data is a model of a part of the real world. The model of data then should probably refer to the methods of manipulating and persisting data. It's a low-level implementation detail detail.
These propositions immediately lie down two things: 1. We're solving the problem of modeling the real world and probably we want to model it with data; in other words, we're interested in "modeling using data". 2. The mainstream tools (SQL and OO when used to describe data) are rather focusing on the problem of "modeling the data", which isn't what we're essentially interested in.