While the differences between Enterprise 1.0 and 2.0 are grey at best, we can attempt to draw some segmentation by reviewing the high level characteristics.  The following table provides a side by side comparison of these technologies.

In the Web 1.0 environment, information was largely static and controlled by a few resources.  Specifically, the individual or organization that produced this information pushed information to the end user by either controlling the access or limiting the feedback options.  Web 2.0 turns that model around and create a far greater dynamic environment where each consumer has the ability to contribute to the overall value of the information itself.  Instead of searching and browsing topics, Web 2.0 users are allowed to publish and subscribe to the content which results is a more bottom up implementation.