Tiger lets you tag items (movies, posts, etc.) on YouTube, Archive.Org, StackOverflow.com, StackExchange sites, Yahoo Answers, Stagevu.com, forum.WordReference.com, and www.GeoGebra.org/forum.
For example, you can tag a movie under "to watch", "russian dance", "funny", "math", "watched", etc. The tags are shown beneath the item anywhere it's shown (e.g., in search results). This lets you find your hands and feet in sites that provide millions of items.
See the screenshots:
To tag a movie (an item) you simply click any of the tag buttons displayed near the top of the page. Or you can create a new tag by typing in the "New tag:" box. (You may delete/rename tags by right-clicking on the buttons.)
Visit Tiger's support page to find a nice user manual and many more screenshots.
== ADVANTAGES OF TAGS
- CLEAN: They don't clutter your browser's bookmarks.
- PRODUCTIVITY: They're displayed almost anywhere a link to the tagged item is displayed.
- PRIVACY: They're stored on your own computer.
- INTEROPERABILITY: You can export/import them in JSON format.
== BONUS FEATURES
Besides providing the tagging facility, Tiger also adds some usability enhancements to the sites it supports.
For example: for YouTube you get clips preview: when you hover the mouse on a thumbnail, a window pops up with three larger thumbnails (from the beginning, middle, and end of the clip). See it in action in the screenshot here. This is a great time-saver: it's your weapon against users who "engineer" their thumbnails to titillate the user. This alone is a reason you might want to use Tiger.
== THE STORY BEHIND TIGER
I originally wrote Tiger to help me use Archive.Org, where I'd download (legally) old movies and so-called "Old Time Radio" episodes once in a while. I later made Tiger work with YouTube, as I grew exasperated with its inadequate "playlists" feature. Yahoo Answers support came in between.
Tiger is available for Firefox and Chrome as well. A GIT repository is used to encourage contributions and transparency.