Women who visit the project’s website, Wemap.org, can drop a pin on a map of the UK to mark a place they have experienced harrassment.
These pins will be displayed on a digital billboard at Westfield London throughout this week (25-29 April).
Ten #WEcount markers have also be place at key locations around the capital, including Camden Market, Queen Elizabeth Olympic Park and Westminster Bridge.
Once users have found an exclamation-shaped marker, they can scan it using the Blippar app to unlock information about the campaign and find out about the support available to them.
Users can then spread the campaign's key messages via social media.
Caitlin Ryan, executive creative director at Cheil London, said: "It's brilliant that the success of this work means women across the country can lend their voices and experience to the fight against sexual crimes committed in the UK."
Omaid Hiwaizi, president global marketing at Blippar, added: "We hope the momentum keeps building in the battle against sexual violence keeps building and that our work with Blippar makes Londoners take notice of the crimes being committed around them.
"Blippar is designed for people to discover more about the world around them – whether that be inspirational or informative. We believe that #WEcount is both and we're delighted to deliver such a powerful message and help women reclaim the streets."
Ryan was appointed creative director at Cheil in January, following a three-year stint at Karmarama.