To inspire people to "uncap what's inside" and express themselves creatively!
Sharpie is a household brand. They are known for being permanent, and they are permanent to stay. People use Sharpies to wrjte notes, set reminders, make presentations, brainstorm, write on casts, get autographs, and my personal favorite: punish drunk friends. They offer an array of point sizes, grips, and sizes in many different vibrant colors. I think that is what makes Sharpie popular - its distinctive bright colors make blending impossible. It makes writing ideas more simple.
If you want your message to be seen, use a Sharpie.
Their advertising target consumers' memories by emphasizing moments when you have used them in the past. It makes your Sharpie feel like a buddy.