Short bio: Computer Scientist, FOSS supporter (read more)
Tux Machines (TM)-specific
Dolphin was intended to replace Konqueror as the default file manager in KDE 4. The scope of Dolphin was to only provide a compact and easy-to-use file manager, without all the features and uses Konqueror has. And (I think) it succeeded. In the beginning most of the users were reticent regarding this idea, since Konqueror provided anything one could possibly ask from a file manager. Besides, most KDE fans thought Dolphin looks too much like with Nautilus and may be limited regarding usability and configuration. However, I see in Dolphin an appropriate manager for day-to-day use.
Dolphin is split in three main components (except for the menubar and toolbar). The first one would be the Places widget, located by default to the left, and containing shortcuts to the most important places like home directory, root, trash, and mounted devices. The center is occupied with the file browser, while to the right there is the file information widget. The good thing is that the Places and Information widgets can be moved and grouped wherever one likes. Another plus is the way the icons in the Places tab resize depending on the tab's width.