Recently we've covered OS X Yosemiteup one side and down the other. Read through our guides for installing Yosemite; getting familiar with the new operating system's design; putting Handoff and Continuity to good use; and learning about changes to Safari, Notification Center, Spotlight, and Mail, Messages, and Calendars. That should give you a pretty fair idea of the changes Apple has wrought with Yosemite. Equipped with this knowledge it's time to ask the important question: Should I update or not?
The big picture
When pondering the wisdom of updating your operating system it can be helpful to understand what its creator was hoping to achieve with the release. For the last several iterations of the Mac OS, Apple has moved away from a computer-focused digital hub strategy where your Mac held and commanded your data and you attached other devices to your computer to sync its data with them (and vice versa).
In recent years, Apple has turned instead to a stuff-centric scheme. In this case your Mac is just another device (although an important one) that has access to your files. What you're largely concerned with is being able to work with those files, regardless of whether you're using a Mac, an iOS device, or accessing them via a web browser. The cloud is a key component in that it provides the means for making your data available to all these points of entry, and transparently so.
Under Mountain Lion and Mavericks this was evident as iCloud was designed to sync much of the data it had under its control--your email, contacts, calendars, notes, Safari bookmarks, photos, music, and files from apps that once belonged to the iWork and iLife suites (as well as TextEdit and Preview documents). With Yosemite, Apple is further loosening the constraints of computing via two broad efforts. The first is creating an operating system that plays better with data outside Apple's control. The other is making it easier for you to work with your data on the most appropriate device available to you.
On beyond Apple
Three key elements of Apple allowing you to more easily work beyond its borders are Spotlight, Notification Center widgets, and iCloud Drive.
Spotlight: In the past, Spotlight was a perfectly fine tool for searching the contents of your Mac, producing dictionary results, and performing calculations. If you wanted to move farther afield you could select the Search Web For or Search Wikipedia For entries at the bottom of the Spotlight menu, which were little more than Safari shortcuts. With Yosemite, Spotlight will now incorporate and provide previews of results from the Internet, including Bing search results, map data, news headlines, Wikipedia entries, Apple's store content listings, and movie showtimes. The net result means more efficient searching and fewer trips to your web browser to find the information you desire.
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