If you use Spotlight Search and the OS X Mail application, you should take a moment to look at your settings. A recently uncovered glitch in Spotlight Search for OS X may leak private information, such as your IP address, to email spammers. The glitch causes Spotlight's preview functionality to ignore Mail's remote content settings, meaning it can unintentionally transmit data to some email senders.
The glitch has been tested and confirmed by IDG News Service. When an email is shown in the preview window of Spotlight Search it also loads images shown in the email, even if Mail's "load remote content in messages" setting is turned off. Some email spammers include tracking pixels in their messages, which send information back to the spammer when they're loaded.
At the moment the only way to fix the glitch is to turn off "Mail & Messages" in your Spotlight settings. You can find these settings in the System Preferences of your Mac.