This is an interesting article that hits on an puzzle I’m spotting more and more.
Increasingly I’m seeing marketing and UX considerations being combined without the combiner’s apparent realisation of that fact. Working across both, I think there’s a difference between persuading a cold someone to sign up and persuading a user to do something they’ve opened your product specifically to achieve. There are other factors at play.
For example, one is the issue of perceived need. If I don’t perceive a need to upload my photos to dropbox, I won’t, no matter how much I like and use dropbox. If I feel the idea of getting paid by an organisation for making a referral is disingenuous, I will likely never make a referral through that site. Your brand may be able to cultivate a sense of that need in me over time, but probably not through a popover feature intro or some release notes — what I’d call product text.
Frequently designers aren’t trained to write copy, let alone microcopy, or persuasive prose. I think it’s not a bad idea to understand the communications goal before you start writing, and know when to get help. Just my thoughts.