Tabs are a very well-known and popular feature in nearly all web browsers. There are a couple methods to open new ones in Safari–my favorite is double-clicking on the tab bar (described here). To close tabs in Safari, one typically clicks on the little “x” at the left-hand side of the tab, presses Command-W, or selects Close Tab from the File menu.
I discovered a new keyboard shortcut in Safari today that offers another easy way to close a tab, which is a part of the Twicetab Safari plug-in. After installing Twicetab, Command-Clicking or Option-Clicking on tabs in the tab bar magically close them! This fits in well with the keyboard shortcut that allows you to Command-Click on a link to open it in a new tab.
Twicetab was originally a very useful application for its feature that allows you to double-click on the tab bar to open up a new tab, but after the Safari 3.1 update came out, I figured Twicetab would be nearly obsolete. However, this additional feature in Twicetab makes it definitely worth checking out.
Twicetab is developed by Infinite Labs, who also develop Afloat, which we covered a couple days ago.