Ak HN: Are iframe-bars inherently evil?

In light of Digg's (Kevin Rose's) recent move (http://digg.com/d31Nfqb The Digg iFrame Toolbar is Dead), what's your opinion on iframe-bars? There are (arguably) good use cases for a "no install needed" "no browser reboot needed" instant and temporary toolbar. At the same time getting users to install a "real" add-on is challenging.

The current browser technologies don't really support the iframe-bar well. So to keep it short: 1. Are they inherently evil? 2. Could a new "eframe" be defined with such semantics to make such use cases possible (I have some ideas but this question is getting too long). Uri