If you’re not using del.icio.us to keep you on top of your game, you’re missing out. Below, find my 22 most indispensable tags:

• boredomkiller – Sites to keep you busy when you just can’t bring yourself to do anything else. My favorites include the Where Did I Take This? Flickr Pool and Amazon’s Mechanical Turk.
• calendar – Event calendars that you check on occasion (i.e. the local symphony or theatre) that you can’t subscribe to via RSS. Go through this tag during your weekly or monthly review and update your other calendars accordingly.
• coupons – A repository for coupon sites like RetailMeNot, or specific coupons you come across in your email or while surfing. Review before making any purchases.
• firefoxextension – An easy reference for installing your favorite extensions if you need to reinstall Firefox or install a copy on a new machine.
• gift – Tag pages with gift ideas for others. (Just don’t tag any gifts you don’t want someone in your network to see!) Review for upcoming birthdays.
• howto – Tag instructions for projects you’d like to tackle at some point in the future, like How to Tie a Tie or How to Make an Invisible Bookshelf.
• journal – Read a thought-provoking question or prompt that you want to write about later, like Gretchen’s one sentence journal? Tag it here.
• keeptabs – For those websites or products that haven’t launched yet and you want to remember to visit in the future.
• idea-[?] – This is my favorite tag, and one I use all the time when I see something related to a project I’m working on (or want to work on in the future). For example, if I see an article with a blog-related tip I want to incorporate on Sufficient Thrust, I tag the page “idea-st.” If I want to save a link for a client, I’ll tag it with the company’s initials. This gives me a small bit of privacy (well, until now!) in a very public location.
• refresher – Motivational and inspirational writing that you want to read again when you’re feeling less-than-inspired. Some of my favorite refresher links include Ario’s Ignite Seattle talk on mortality and user experience and Craig Harper’s Fat by Choice.
• shopping – General shopping sites that you like (or think you would like) to browse, like Bamboosa or Artocracy. (Hint: Adding additional tags like “shoes” or “furniture” can help you narrow this category down further.)
• somedaymaybe – GTDers know the drill. Anything that you may or may not want to do at some point in the future, like “go skydiving” (with a link to a local skydiving service).
• tobuy – Items you want to buy, but can’t or don’t want to buy right away. Examples include: cosmetic recommendations, clothes, new speakers, etc. Include in your weekly review.
• todo – Anything you want to take care of in the near future, like recover space on your iPod or download TiddlyWiki. Process during your weekly review.
• toitune – Songs or artists you want to sample and potentially purchase. Maybe you heard them on the radio, or saw a list of tranquility songs on a blog post. Include in your weekly review.
• tolearn – Always wanted to know more about Austrian economics, Buddhism, or how to improve your memory? Tag it here and review periodically when you’re in the mood to learn something new.
• tolisten – Audio files you want to listen to later. This is especially useful when you’re at work for saving things you want to listen to at home. Include in your weekly review.
• toread – Any page you want to check out at a later date. This is a great place to store longer blog posts or site recommendations, and a great place to find items to print out and take with you for a wait at the doctor’s office or on the subway. Peruse at your convenience.
• toreadcomments – Forget subscribing to comments and potentially having to sort through a stack of irrelevant emails or feeds. Use this tag on posts you want to return to later to read responses. I use this all the time at sites like The Volokh Conspiracy.
• tosignup – Sites of interest that take more time to signup (and setup your profile) than you have at the moment, like Zaadz or Reality All-Starz. Include in your weekly review.
• towatch – Videos you want to watch later, from quick YouTube clips to full-length movies. This is especially useful when you’re at work for saving things you want to watch at home. Include in your weekly review.
• wordpressplugin – For easy reference, each time you install a WordPress plug-in, tag it in del.icio.us. If you decide to launch a new blog, or lose your old one, grabbing your favorite plug-ins will be a snap.

What tags am I missing? Feel free to share in the comments!