Can social media really compete with mainstream media when it comes to reach and ROI?

From the agenda and list of attendees it looks like it will be a decent event and I've been asked to present a case study on how Asda has let go of its brand in order to build a credible YouTube presence, in less than 18 months, by harnessing the power of influencers.

It's been a fascinating period, which started in earnest just over two years ago when YouTube put us in touch with Gleam Futures. Since then we have been refining our ways of working with key influencers, which I believe can be applied to multiple other brands, retailers, and social media campaigns.

The key is having the confidence to let go. Our latest Halloween activity confirmed in my mind social media can not only compete with traditional broadcast media, but it can beat it.

In PR and social media it is often hard to demonstrate a clear return on investment regardless of how you choose to measure effectiveness. Be that reach, pound for pound vs paid for views, positive engagement, click through rates, or sales. However, our #asdarknessfalls campaign demonstrates the art of the possible.

Over a three week period we created three talent led videos for our Mum's Eye View portal, created two paid for Instagram posts, nine scheduled tweets, and seven paid for vlogs on a range of talent YouTube channels.

The first video was by one half of Pixiwoo, Sam Chapman, who created a make-up tutorial featuring a cat make-up set available at Asda. The video generated 36,000 views, and a healthy click through rate (CTR) of 1.6 per cent, but importantly also contributed to a noticeable uptick in sales both in store and online.

Next up was a baking video with Anna Saccone Joly also featuring a Halloween product from Asda, this time fun ghost cake pops. CTR was seven per cent this time, meaning more than 7,000 people chose to follow the link to our dedicated Halloween site. It also helped spike sales upwards.

Instagram is a great platform to share fun images, but harder to judge CTR as you can't embed links in the text. That said over quarter of a million followers of Joe Sugg liked his post about one of our hero products a creepy crawling green hand (pictured), which is a fairly decent return and a good proxy of engagement and reach.

In addition Anna posted a link featuring her kids in Asda Halloween costumes on Instagram, then linked to it on Twitter which helped extend the reach and drive 3,500 more clicks.

Then came the event itself.

This year marks the third year running that Asda has sponsored the annual YouTubers Halloween party where 100 of the most influential YouTube vloggers in the country gather in one place for one night.

The format is straightforward, seven of Gleam's talent are commissioned to go to Asda in advance of the event to get their costumes and make-up. They post blogs to their daily vlog channels, and use the Asda hashtag which is deliberately subtle #asdarknessfalls.

The results are staggering.

• 45m impressions
• 4m video views
• 215k thumbs up
• 34k clicks to Asda.com

I could go on.

We also benefit from lots of other vloggers sharing pictures of the night, standing in front of the Asda step and repeat board. Not surprisingly the hashtag trended at various points during the day and evening itself. And the entire three weeks of activity cost the equivalent of a days’ worth of national press ads.

Zoella's vlog alone was a twenty minute advertorial of Asda's Halloween range both in store, then in her home which she decked out. We saw a 488 per cent uplift in sales within 48 hours.

So what are the key learnings?

Firstly as brands, creating great content on its own is not enough.

Working with key influencers allows you to rent their audience.

When you get it right it is more cost effective than other forms of paid for media.

However, we are still only scratching the surface of what is possible by working with influencers. And the ultimate goal would be to integrate this activity through the line in a truly multichannel way.

The results would be scary.

Dom Burch, senior director of marketing innovation and new revenues at Walmart (Asda), explores the ever changing world of social media marketing in his 'Thought of the Day' blog. You can follow him on Twitter at @domburch