The main problem with Smart Tags is its commercial aspect, not the technology behind it. Keep in mind that the XLink specification which extends XML allows precisely this kind of thing; it even goes further by allowing one to annotate read only web pages by embedding your own content via an xlink. One can imagine this being done for personal use (i.e. sticky notes on the web) as well as commenting on other people's web site by linking to it from one's own. Once the legal issues are all sorted out, I imagine this will be a positive thing.
See also The Annotea Project.
Slashdot Mirror
The main problem with Smart Tags is its commercial aspect, not the technology behind it. Keep in mind that the XLink specification which extends XML allows precisely this kind of thing; it even goes further by allowing one to annotate read only web pages by embedding your own content via an xlink. One can imagine this being done for personal use (i.e. sticky notes on the web) as well as commenting on other people's web site by linking to it from one's own. Once the legal issues are all sorted out, I imagine this will be a positive thing. See also The Annotea Project.