What is Mindspark, & should I delete it?

To answer your question, chute --

Mindspark Toolbar got on your computer after you have installed a freeware software (video recording/streaming, download-managers or PDF creators) that had bundled into their installation this browser hijacker. This browser hijacker is also bundled within the custom installer on many download sites (examples: CNET, Brothersoft or Softonic), so if you have downloaded a software from these websites, chances are that the Mindspark tooolbar was installed during the software setup process. Very often users have no idea where did it come from, so it’s not surprising at all that most of them assume that Mindspark Toolbar is a virus.

The Mindspark Toolbar it’s technically not a virus, but it does exhibit plenty of malicious traits, such as rootkit capabilities to hook deep into the operating system, browser hijacking, and in general just interfering with the user experience. The industry generally refers to it as a “PUP,” or potentially unwanted program.

It should be in your Safari Extensions list.

From the Safari menu bar, select

Safari ▹ Preferences... ▹ Extensions

Remove all extensions that you don't know you need. None is required for normal operation.