There’s no question that this is the age of the influencer.

But is that spike caused by Stephen Fry’s single tweet more valuable to Prostate Cancer than an ongoing series of tweets, blogs and digital advocacy from a passionate, credible health blogger with just 1% of Fry’s following (which would still be an impressive 87,000)?

To answer that, you need to decide what you’re looking to get out of this relationship.

Clearly, with massive scale, there’s the potential for a one-off mass awareness hit for your charity or campaign (and a welcome increase in donations).

And if that’s what you’re after, then Fry’s your man – or perhaps Zoella for a younger demographic (By the way, nice move by the BBC to sign her up for Red Nose Bake Off). Agree a tweet, hand over £5,000… job done.

However that might not go down well with your supporters, as Barnardos found out when it paid someone from Made In Chelsea £3,000 to front its latest campaign.

Might you be better served by seeking credibility and authenticity around a topic or passion point?

By this logic, a top UK baking blogger and cookbook author such as Sarah Trivuncic (aka ‘Maison Cupcake’) is the right person to engage around a Macmillan Cancer Coffee Morning campaign.

She offers access to her large, highly engaged following, has an audience that trusts her recommendations and opinions implicitly, and – of more importance – offers an opportunity to engage them multiple times, thus nurturing genuine charity advocates (and more regular donations).

This option can be more effective in the long run, but needs careful preparation in terms of influencer selection, outreach and handling.

To achieve maximum effectiveness, keep these six key points in mind…

1. Research

Finding the right influencers, with the right passion points and audience interests, is crucial if you are to drive engagement with their audience.

Thrifty food blogger Jack Monroe’s followers would raise an eyebrow (rather than money) if she started to make a song and dance about declining biodiversity on behalf of WWF.

But Oxfam and Live Below the Line speaks to her personally – and thus her partnership with them has hit the right note with her followers.

2. Relevance

You wouldn’t tell eBay how to auction goods. So don’t stipulate the blogger’s output – co-create.

They’ve nurtured an engaged following through their own personal observations and content, so why mess with that?

Give them the information or assets they need, then leave them to do what they do best – after all, there’s a reason you approached them.

3. Respect

If you’ve done your research and matched the right blogger with the right charity, they will want to shout about you from the rooftops.

They might even do it for free – bloggers tend to see it as the equivalent of volunteering.

But don’t presume. Their influence is their income, so some sort of value exchange is only polite – from a campaign-branded T-shirt to a trip abroad.

4. Relationship-building

Sport Relief getting David Walliams to swim the Thames is spot on: that’s months of training, meaning months of newsworthy content.

It’s now a long-term relationship that’s seen him return to, and mention, the cause again and again.

If you’ll looking to build advocates, tailor your approach to stimulate a sustainable partnership – it will yield extra earned media long past your initial outreach date.

5. Real-time reaction

An influential blogger tweets about your campaign, and you send an excited email about it round the office.

Engage with them during your campaign, retweet them, favourite them… make them feel like an extension of you and your organisation.

It’s also an idea to monitor the blogosphere between campaigns, as influencers tend to come up with their own campaigns and you could get lucky (see ‘Team Honk’ – an organic blogger campaign that proactively approached Sports Relief).

6. Rules

…the recently-released ASA rules, in fact.

Always, always encourage your bloggers to declare the ‘sponsored’ nature of commissioned content.

Of course, a long-term relationship can yield non-paid for, organic content that equates to free earned media without the ‘sponsored’ tag… the charity sweet spot.

For more on this topic read our posts on five lessons for effective blogger outreach and the 10 most common mistakes of blogger outreach.