A modernization of the DSLR is to remove the mirror and its components (optical viewfinder, phase detect autofocus system, etc.) and perform the functions those components provided using the imaging sensor and the color LCD (sometimes supplemented with an electronic viewfinder, or EVF).
Removing the mirror box allows you to put the lens mount closer to the sensor (requires redesigning lenses, though), making for a smaller camera in depth. Quite a few other components that need critical alignment in manufacturing are also removed, making assembly quicker and less expensive. The down side is that using the image sensor to perform exposure and focus and using the color LCD or EVF to display what the camera is seeing consumes more power, produces more heat, and is (at least for the time being) lower in some aspects of performance, such as focus speed. These trade offs make mirrorless cameras (also called Interchangeable Lens Cameras [ILC] or Interchangeable Lens Systems [ILS]) good at competing with entry-level DSLRs, but not as capable as high-end DSLRs.
The Mirrorless Camera Timeline (links are to my reviews)
- Sep 2006: Leica M8
- Sep 2008: Leica M8.2
- Sep 2008: Panasonic G1
- Mar 2009: Panasonic GH-1
- Jun 2009: Olympus E-P1
- Sep 2009: Panasonic GF-1, Leica M9
- Nov 2009: Olympus E-P2, Ricoh GXR
- Jan 2010: Samsung NX10
- Feb 2010: Olympus E-PL1
- Mar 2010: Panasonic G10, Panasonic G2
- May 2010: Sony NEX-3, Sony NEX-5
- Jun 2010: Samsung NX5
- Sep 2010: Panasonic GH-2, Samsung NX100
- Nov 2010: Panasonic GF-2
- Dec 2010: Samsung NX11
- Jan 2011: Olympus E-PL2
- May 2011: Panasonic G3
- Jun 2011: Olympus E-PM1, Olympus E-PL3, Olympus E-P3, Panasonic GF-3, Pentax Q, Sony NEX-3C, Leica M9P
- Aug 2011: Sony NEX-5N, Sony NEX-7
- Sep 2011: Nikon J1, V1, Samsung NX200
- Nov 2011: Panasonic GX1
- Jan 2012: Fujifilm X Pro 1
In addition to the still cameras, two companies, Panasonic and Sony, have made video cousins to their mirrorless cameras:
- Panasonic AG-AF100 (2010)
- Sony NEX VG-10 (2010), NEX VG-20 (2011), and FS100U (2010)