when I read up about modal dialog boxes and their use, there is a lot of discussion on how they interrupt the user's flow and how they should be used sparingly.
There are other issues that people have sighted with the use of Modals conflicting with the "Back" navigation on the browser. There are others who cite research on how they add to the cognitive load.
I agree with all those points, but they do bring value to the table which has to do with ensuring that the users can do other tasks without having to navigate away from the context
I see this being used in several popular sites such as
- Facebook: Using lightboxes to show larger photos
- Gmail: Compose message (it has two modes one is stuck to the bottom but another that is an overlay/modal/lightbox)
- JIRA: To create issues and tickets
- Amazon: To show close-ups and different angles for products .. am sure there are many more here
there are a few people who have spoken about this aspect and have accepted their utility as a navigation tool..
People appreciate being able to accomplish a self-contained subtask in a modal view, because the context shift is clear and temporary. IOS guidelines (http://tableless.github.io/exemplos/pdf/guidelines-interface-mobiles/MobileHIG.pdf) cited by (https://ux.stackexchange.com/users/5058/naoise-golden)
I have also read through several discussions including this one The Usability of "Lightbox UIs" (one of the better discussions on the topic)
I would really like to know what is the general feeling NOW that they have been around for so long and seem to be very widely used. Most of the other discussions are very old like the one quoted which dates back to 2010.