iOS/Android/Mac/Windows: iDisplay, a utility that turns your tablet into a fully-functional second screen for your computer, just updated with a big speed boost, much lower latency over Wi-Fi, and support for Android tablets and OS X El Capitan. We've mentioned iDisplay before, but back then it was iOS, Mac and Windows only. In the time since then, the platform has come to support Android devices, and the latest update offers a huge speed improvement and lower latency times that make using your tablet as a second screen much more reasonable, as long as it's on the same Wi-Fi network as your Mac or Windows machine. The latest version supports OS X El Capitan, and there's a Windows 8 beta (Windows 10 still isn't supported, but is coming soon according to the devs).
Still, the new version's speed improvements are inching ever closer to solving the big problem with using tablets as second screens -- they're just not fast enough to be worthwhile. Now you can watch your social streams update in real time without having to poke the display, or even type in a document on your tablet from your desktop without waiting for whatever you said to appear.
Even so, it's still on the pricey side. The desktop apps are free, but the mobile apps are where you'll spend money. The iOS version is $14.99, and the Android version is $US5.86 ($8.26). If you're looking for alternatives, we have our favourite picks here for iOS and here for Android.