Tumblr Tag Explorr lets you search Tumblr for multiple tags at once. This is not the same as searching for posts with multiple tags. An example: letâ€™s say I want to see all posts on Tumblr tagged cats together with all posts tagged dogs and also all posts tagged penguins. The Tumblr search only lets me find posts that have all three tags so I would have to make three separate searches.
With Explorr you can perform those three (or two, or five or more) searches simultaneously.
HTTPS version is also available and the URL gets updated with the tags you searched for, so you can easily bookmark the page.
For more detailed description and example usage visit http://blog.fourtonfish.com/tagged/tumblr-tag-explorr
Note: This is an early beta and the app may feel a bit clunky, but I am slowly working on polishing it.