I want to create a tag cloud where if user clicks on a tag, the tag cloud shrinks to only show tags that have been associated with the tag that the user clicked on. Again, if the user clicks on a tag, the tag cloud shrinks again, refining tags in the cloud to only show tags that are associated with both of the previous tag words. Want to have breadcrumbs to display tag drill-down so user can go back to any point in the tag cloud drill-down process. At any point along the way, user would be able to click "show results" to see all results that contain associated tag words. Think of it as a "drill-down" tag cloud if you will. Any ideas?
That sounds very cool. You'll be using whatever flavour of ajax you already use on the site (jquery, prototype etc). Effectively for each click you'll either a) be returning the complete cloud or b) a small javascript script that changes the className of each item according to its relevance. a) would include the breadcrumbs b) you'd need to use javascript to update the div that holds the breadcrumbs - although it could be just the breadcrumbs div that is updated in the first place and the javascript is within that div because it doesn't really matter where the script is physically.