As the owner or administrator of a web map, I have a preference on what the public or viewer of my web map should see. As far as the 'details' tab on the left side (about, content, legend) I would like to have the ability to designate what will be the default view for the viewer. Often times the public is unable or unwilling to figure out there are different tabs to cycle through.
Perhaps I want them to read the important details in the about tab. Maybe I want them to see what the different colors mean in the legend. What if it is critical they notice there are other layers to turn on/off in the contents tab. Maybe I don't want the tab there at all?!?! As the web map creator I would prefer to have the ability to determine the default details tab displayed.
This would be a great addition to ArcGIS Online functionality. If you like the idea vote it on up and hopefully we'll see it in a future update. Thanks!