If you want to be able to tag websites when you find them, then you will need the Delicious buttons on the Browser (Internet Explorer, Firefox or Safari) you are using.
Type your user name and password, press Enter on the Keyboard.
Click on Bookmarking buttons and add-ons for your browser or website under the Need tools?
Click on Internet Explorer buttons if you are using Explorer
Click on Bookmarklet buttons for any browser if you are using Safari
Follow the instructions for installing buttons