Distill Your Startup Down To A Meme

A meme is "an idea, behavior or style that spreads from person to person within a culture."

So before you spend lots of time and effort in trying to spread your startup - make sure it's something simple and attractive enough that it can spread as frictionless as possible between people in a group.
Boil down your startup to its most basic essence - and that will make it memorable. Some startups like Reddit tie that simple idea to an iconic mascot; others like instagram have a simple icon that simply stands out from the rest.