It’s the question content marketers dread. Just like the first time a child asks how babies are made. Where do subscribers come from?

It’s easy to argue how great content can keep prospective buyers engaged, build your brand reputation and save a fortune on above the line campaigns. But how do people find the content in the first place? Well, often they click thru to it from email campaigns. Okay. But where do the email subscribers come from?

According to a 2013 marketing ‘Sherpa’ study, 77% of marketers ask people to subscribe on their website. It’s often in the form a sign-up form in the sidebar or the header. A consistent placement on every page means more people will see it, without feeling that you are trying too hard to grab attention.

Giving it different treatment on different pages can attract more attention, but also turn people away. Similarly, a pop-up lightbox can be very effective if you delay its appearance until the browser has spent some time on your site.

Another popular way of building a subscriber list is through gated content. You get people to sign-up to receive something of value – a guide book for example – and add them to your email list. Be careful, though. If you don’t tell them about the newsletter your new subscriber might not welcome your emails and consider it spam. You’ll quickly undo all the good word your website and content has done for you.

Landing pages can be another source of subscriber sign-ups. Links from an advertisement, for example, might point to a specific page tailored to the campaign message. The fact that the visitor has clicked thru shows a certain amount of interest in your offering, so there’s less risk in going hard on the benefits of joining a mailing list.

I’d be surprised if most marketing savvy companies aren’t deploying at least some of these approaches to list generation. Then there are the opportunities during the sales process – either in the checkout process online, or at the sales counter in-store. These people are buying from you, so it’s a relatively easy pitch to suggest they might like to be kept informed of future offers.

But there are some interesting new ways of gathering subscribers. Like Twitter’s Lead Generation Card. It’s an expanded Tweet that can include a specific offer and a form in which the user can enter their details, without leaving Twitter. Or you can ask people to sign-up via a link on your Facebook page.

The key to any approach is to be genuine and trustworthy. If you try to hoodwink a prospect into subscribing the outcome will be the opposite of what you intended. Being upfront and trustworthy is essential when acquiring subscribers.