But for what advantage? What are the chances that I type my mail, phone and address completly wrong so that the sender can't contact me at all? I don't see any advantages in that validation.
Well exactly this is the total wrong approach. This does not work at all. For example you will find myself not in address nook neither is my mobile phone number in any public phone book. A customer knows exactly how his address is written and furthermore mail services are most of the time able to figure out where the delivery belongs to
If the address is not clear. As mentioned by the other comments above, there are so many exceptions. This is a pretty good article about zip code: http://www.mjt.me.uk/posts/falsehoods-programmers-believe-ab...
Being skeptical on things that get written on the internet is always a good idea ;) And I am thankful to everyone who brings constructive criticism. Unfortunately I haven't seen any information regarding research from sites that use those approach. Would be interesting to see them.
I agree that a full page load is not required. Also I didn't intend to recommend to use the normal progress bar. It is just from a user perspective a duplication of the bar above. What I intended to say is, that the loading bar should not be used to show a progress is going on. Because the page stays more or less the same and the user is looking with a very high chance at a different area.
The progress bar within does work, because the user enters the address right there and at the moment where he presses enter, his eyes are still in this area, so he recognizes the progress bar immediately. A unmissable loading bar would solve the problem, as long as it is unmissable (from my point of view).
Why should my statement be speculative? Ok, one could mention it that way because I have not done any research during any university in this field, but it reflects my personal experience and the experience I do have from past projects, when user tested certain pieces of software.
This blog entry is based on my personal experience in the field of user experience. I have not done research on a university level. I do have a lot of discussions regarding the distractions of user interface with non-technical users which exactly get confused by such behaviors. That is why I can't link any citations and studies.
Using the existing status bar would be a better approach from my perspective, but still does not replace any status indication at the point, where the action is triggered.
I have not written (or at least I have not intended to write) that using the existing status bar is a better approach to show that progress is going on. At the end of the article I stated clearly that the progress indication should happen at the point where I execute the action.
But even when the complete page is reloaded in an ajax/pjax manner, the loading bar is out of the visibility area. If one scrolls through the recommended videos on YouTube and pick one which is in the middle or below the list, one will not directly recognize the loading bar - why not showing the status indicator in a more prominent place?