Microsoft has released Skype 6.7, which completely overhauls the telephony app’s search feature. Now you can enter a term into the toolbar’s search field, and it will bring up a list of relevant conversations, as well as enabling you to explore your entire conversation history. A number of issues have also been resolved, including Skype hanging when closing the application during a call, being unable to hang up a call with the keyboard shortcut, and duplicate messages to Facebook contacts. There is an existing known issue with Mac OS X 10.7 Lion where the app sometimes crashes when clicking on profile pictures or file transfer icons. If Skype’s automatic update feature hasn’t yet gotten you the new version, choose Skype > Check for Updates, or download a copy from Skype’s Web site. (Free, 40.6 MB, release notes)
Go Back and Forth Fast in Preview
If you're reading a PDF in Apple's Preview software, and you follow a bookmark or an internal link to move around within the PDF, you can quickly return to where you were by pressing the keyboard shortcut Command-[ (that's Command-Left Bracket). Or, you can choose Go > Back.
The command works iteratively, so you can go back to just the previously viewed page or if you issue the command again, to the page before that, and so on. There's also an equivalent Go > Forward (Command-]).