Vincent Danen discusses the new and improved Services menu in Snow Leopard and gives several examples of what you can do with it to improve productivity.
For as long as OS X has existed, there has been the Services menu. It hides under the application's primary menu bar as a pull-down and can have some really cool things hiding in it. Unfortunately, it was traditionally cluttered with every service available from every application installed. Worst of all, depending on context, a number of items would be greyed out and unavailable, which made the Services menu relatively useless. After all, who wants to scroll and sift through all those entries to find someting relevant? Sure, if you knew what you were looking for it was great, but if you didn't, it was more of a chore than the timesaver it should have been.
The Services menu is supposed to allow you to save time and do cool things. For instance, if you were in the Finder, selected a file, and then used the menu bar to navigate through Finder | Services | Mail | Send File, the selected file would be attached to a new email message in Mail.
Mac OS X 10.6 changed the Services menu so that it is actually useful. Extremely so, in fact. For one, it is contextual, so based on what you are doing, it will provide relevant entries. Gone are the days of lists of greyed-out items in the Services menu that no longer apply.
If you highlight a piece of text, only those entries that would do something with the text (create a new note, a new email message, etc.) will show up in the Services menu. Select a file in the Finder and only those Service items that are relevant (such as sending a file to EagleFiler or creating a new message with the item as an attachment) show up. This makes the Services menu so much more manageable and appealing and, ultimately, useful. Another nice feature is that the right-click (or CTRL-click) contextual menu also shows the relevant Services entries (although there is a bug in 10.6 where not all of the applicable items show up in the contextual menu all the time).
There is one more really sweet feature with the new Services menu. In System Preferences, visit the Keyboard preference pane. There, visit the Keyboard Shortcuts tab. This is where you can assign global keyboard shortcuts to various features. Amongst the list of Dashboard, Front Row, Spaces, and Spotlight shortcuts is an entry for Services. When selected, you can go through the list of all available services and further tweak what is shown in the Services menu. Have Camino installed, but it's not your primary browser? Why have the "Open URL in Camino" item in the Services menu then? Here you can place a checkmark beside those items you do want available in Services and, just as importantly, take the checkmark away from those you do not.
As well, if you double-click the shortcut (hint: double-click the space on the far right of the line to get the entry box!) you can assign a custom keyboard shortcut. Of course, these are context-dependent as well; you can assign the keyboard shortcut CTRL-OPT-CMD-I to "Get Info" for files selected in the Finder and it will do nothing on highlighted text in TextEdit.
Finally, a new Automator document type was created to handle creating custom Services. This means you can create an Automator workflow as a Service and have it available to you regardless of the application you are in.
While the Services menu may have been largely ignored in 10.5 and earlier, I think we will see a lot of extremely creative workflows and applications becoming available for 10.6 that leverage the new Services menu functionality.
Vincent Danen works on the Red Hat Security Response Team and lives in Canada. He has been writing about and developing on Linux for over 10 years and is a veteran Mac user.