We have a requirement for a website where there will be a contact form on screen in all pages as well as the ability to signup for a newsletter.
Now, a contact form is something traditionally done in the footer (if it's required to be available for all pages), where we'd have a form for entering the email address, query text and submit button.
For signing up for newsletters we need the email address field.
That brings up the following dilemma:
Should I make the same form cross-purpose so that you can sign up for the newsletter at the same time as making an enquiry, or have them as two separate forms?
I've mocked up both versions into one wireframe here, but it should give an idea of the two options. There will be other stuff in the footer so it could end up cluttered if there are two forms and a load of content in there.
download bmml source – Wireframes created with Balsamiq Mockups
The plus point about mixing the two is that it is possible people will want to do both actions - contact us and request a newsletter. One single form means they don't have to fill their email in twice. However it gets a bit confusing if they only want the newsletter, because they're filling in an enquiry form when they don't actually have an enquiry. Therefore it makes more sense to have a separate field for newsletter signup. But of course that means the footer of this page is going to have two different forms in it, both with the same 'email' field.
I'm probably overthinking things here, but I wonder if there is a better option to go for so that I'm not duplicating functionality in the same place and having loads of form fields everywhere in the footer, but also keeping things obvious about how you enquire and how you request a newsletter.