You decide which plugins to install, then Spotlight can do even more for you. There are a wide variety of plugins available such as Discogs for performing specific searches, one for sending an email right from that Spotlight entry window, and even one to send things straight to your OmniFocus Inbox.
Once you download the free Flashlight app, you can launch it and from the main window and start enabling the plugins you want to use.
Here's the main Flashlight window.
It's easy to tell if the plugin you want is installed or not; there's a button that shows either “Install” or “Uninstall” on each one in the list. You don't have to browse the website for plugins or worry about a convoluted process for downloading and installing them.
Flashlight's main window is a one-stop shop for everything it does. There's no real preferences to configure or anything else; once you install plugins you're ready to rock.
This is the magic of Flashlight: once your plugins are installed, you just need to start using them. Hit Command-Space (or whatever you've configured for Spotlight) and start typing. Easy things like a wider variety of targeted searches are handy, but also more clever items like copying hex color values from the color picker, or even sending an iMessage are possible right from the Spotlight window.
Here's the message I sent Bryan. Both to test the app and his patience.
If you have a bit of programming skill in Python or Javascript you can create a plugin that does something clever from the Spotlight window. If you don't have any inspiration, or you have all the inspiration and no code skill, check out the Ideas page to see what other people have submitted as things they'd like to see.
Honestly, I never really used Spotlight until Flashlight came along. Even with the added functionality in Yosemite it never caught on with me, but thanks to Flashlight's ability to configure it to do all these other things made it something that now pops up regularly on my screen. It's the sort of thing that can shave time and steps off your workflow, so it's definitely worth a few minutes to browse the available plugins and see if Flashlight is for you.