To create a memorable user experience, attention has to be focused on certain aspect of the visual interface. One key aspect of a UI is the Sign-Up/Sign-In form. There have been debates over time about how and when the Sign-Up/Sign-In form should be introduced to the user. Most common design we see around safely opt for convention. But what really determines where/when the Sign-In/Sign-Up form should be introduced in an application?

WORLD VIEW

Some people go to the super market to make purchases, some go to window shop. If the window shoppers find a new or exciting product, they can easily be converted to make purchase.

In the same vein before you open an account with a bank, you must have basic information about the bank that will help you in decision making.

IN APPLICATIONS

Mobile and web applications should be able to replicate such experience since users may want to preview the app before they commit by signing up.

E-commerce/online store applications could easily replicate such reality by giving users the freedom to roam about catalogues of items. And the Sign-Up/Sign-In form may be introduced when the user carts or proceed to checkout item(s).

Bank and Financial applications on the other hand may not be able to replicate such kind of experiences for they may require users' data to deliver their services.

Gaming applications have been known to have arguably the best user experience. Most gaming applications easily replicate this process by allowing users to Sign-Up as random guest and when they want to commit or personalize their experience, Sign-Up with their details.

It is also noteworthy that some users don't want to preview, they just want to get started on-the-go. So design should be made to accommodate such users.

Finally, we can conclude that the main determinant factor to where the Sign-Up/Sign-In form can be introduced to the user in a UI is based on both the target users and also the type of application.