By 2020, millennials will account for one third of all retail spending. They've never experienced a world without the internet, and increasingly they shop, socialise and share content on mobiles.
Millennials also don't trust traditional advertising.
They prize authenticity and transparency, they don't have much brand loyalty and they are more likely to turn to friends, social networks such as Pinterest, or YouTube video bloggers for recommendations rather than traditional buying guides such as magazines.
Primark's Primania website is a great example of how to get millennial marketing right.
It's a cross between a photo sharing service and a fashion magazine where customers upload photos of them wearing Primark outfits.
Primark mixes in some editorial, links to its blogs, provides sharing buttons for all the major social networks and of course, tells you what each product is, how much it costs and where you can buy it.
It ticks all the boxes: it's social, it's fun, it makes customers feel like stars and it gets people buying Primark clothes.
Mobile is all that matters
Millennials are constantly connected.
In a late 2014 study of smartphone and tablet-owning millennials by Survey Sampling International, nearly half of millennials said they use the mobile internet for four hours every weekday and nearly one in three exceeds five hours of daily use.
According to a 2012 study for Time Inc, millennials switch media types 27 times every non-working hour. They consume information buffet-style, and they're keen to share what they've discovered.
Of the four daily hours millennials spend online, most of it is spent communicating. 114 minutes of texting, 99 minutes on social networks and 85 minutes on instant messaging such as WhatsApp.
Embracing mobile has significant implications for marketers, not least because Google now ranks sites that work well on mobile devices above sites that don't.
Slow sites, wordy page titles and descriptions, impenetrable blocks of text and landing pages that sell too hard don't work on mobile, although of course there needs to be clear calls to action.
Search is different on mobile too.
When somebody on a smartphone searches on Google they'll see fewer search results than they would see on a laptop.
Search for 'iPhone' and you might only see one organic search result, the rest of the screen is filled with a mix of PPC adverts and Google shopping results.
If those ads are yours, you can't waste a single word.
Sell sizzle, not sausages
According to a Harris/Eventbrite poll in 2014, 78% of millennials said they'd rather spend money on a desirable experience than buy coveted goods (although Eventbrite is a ticket firm, which may have influenced the study somewhat).
However multiple studies report that millennials value novelty, personalisation and shareability. They want content that amuses, excites or entertains, and products they can show off to their approving peers.
If you want to catch their attention, you need to appeal to their sense of adventure, engage with them and give them something they can share.
Millennials trust their peers and distrust traditional marketing.
Millennials research companies and products online before buying.
Optimising your site for mobile isn't just about millennials. It helps your Google rank too.
Millennials value novelty, personalisation and shareability.
Mobile is the watchword of the millennial generation.
Written by Chloe Basterfield