I quite liked the idea of Smart Tags. Unlike "Smart Tags Are Evil" Scoble.
I like the way Smart Tags work in Word documents, and I wish they'd been included in IE. Perhaps not in the "sponsored" format that was mooted (links to MSN/Google properties, etc), but in a more fundamental user-configurable sense, I like the idea.
It'd be so useful to have a content recognition engine, and to let users plug in an array of tools that they want. For example, if I see a support incident ID on a web page (SRXblahblahblah) and it doesn't have a hyperlink, why shouldn't I be able to define that item as being hyperlinkable to the site of my choice? Why not take one of a set of actions I define based on that content? Dial a phone number with Skype? IM someone by email alias? Look up someone's location on a map? If it saves me a useless start-other-application-then-copy-and-paste some information, then why not?
Further: what if the website I'm using is internal? Why should a web page developer (or content author) support my desire for an internal hyperlink, when they can't even see or test the result?
Back in 2001, Smart Tags might have saved me a bunch of time spend developing interop code for web applications that wouldn't have needed it if a simple client-side tag could have been implemented.
So actual technology: very useful. Intended purpose is at issue. Guess I'm just a "glass is half full" type of person.