del.icio.us' tag filtering provides an excellent interface design for filtering tags without having to scan your tag list or tag bundles, which can turn out quite long over time. In a control area that looks and behaves like a hybrid breadcrumb trail, you enter a tag into an input. Tag suggestions are provided as you type. Build up that filter by adding tags, and each tag in your crumb path can be removed independent of the path you took by clicking the tag's adjacent X icon.
1. The tag filtering UI.
2. Adding a tag and viewing auto-complete or type ahead suggestions.
3. First tag, "iphone," added and you can see the tags that may be combined in the right sidebar under "Related Tags."
4. Second tag, "hacks," added and Related Tags is narrowed further.
5. Original "iphone" tag removed, and now viewing only "hacks."
