I like the del.icio.us Buttons for IE but they don't work as well with IE7. Or more to the point, IE7 has changed the interface model on del.icio.us. Hopefully, del.icio.us Yahoo! will update the buttons sometime soon.
Basically, IE supports a variety of extensions. On such extension mechanism is a "Browser Extension" (catchy, ain't it). While I'm sure there are other aspects to Browser Extensions, it puts a button on IE's main toolbar. An example of a browser extension that I use is Password Scrambler. del.icio.us, in comparison, creates a toolbar with two buttons - one brings up the link post page while the other is a dropdown menu that brings you to various places within del.icio.us. Frankly, I only use the link post button.
The issue is that in IE7, they've moved around the main toolbar. Under IE6, I would position the del.icio.us toolbar right after the main toolbar. So it worked out great. Now, in IE7, the main toolbar is now to the right of the tabs. By default, the browser extension buttons aren't visible, but they are available on the Tools drop down menu. So I don't have one click access to the Password Scrambler any more, but I do have all those extra commands grouped together. But since del.icio.us has it's own toolbar, there's no place really to put it that doesn't take up screen space. It can't go on the command bar with the address box and the search box. It can't go on the command bar with the tabs and the main menu. The only alternative is to have it on a bar by itself, which is a waste of space. Esp. since I only care about the link post button, which would fit nicely on IE7's new Tools menu.
I investigated what it would take to do it myself, and frankly I'm slammed with much more important things to do. At least, more relevant to my day job. Anyone with a good suggestion here, I'd sure appreciate it.
Update - According to a comment left by britta, the del.icio.us buttons IE7 ready yet and they suggest using these buttons in the meantime. Thanks for the tip, britta!