Sony has the distinction of having released the first commercially available digital camera back in the summer of 1981. It was called the Mavica, recorded pictures onto a small disc that was then put into a reader which displayed the images on a CRT. It wasn't an actually digital camera the way we know them today; it was more like a film camera that took freeze frame shots.
15 years later, however, Sony introduced the Cyber-Shot and it was among the first digital cameras that you could use to display pictures on a PC (others were the Apple QuickTake 100, the Casio QV-11, and the Kodak DC40). In 1998, Sony introduced Mavicas that used standard floppy disks to record pictures. Though floppies only held 1.4MB, that was enough for a bunch of compressed 0.8megapixel JPEGs!
As the megapixel race heated up, it quickly became obvious that floppiess weren't the way of the future as far as storage technologies go, and Sony began experimenting with various fom factors, some of them pretty unusual. To this day you can buy Sony digicams that record onto optical discs instead of one of the many variations of Sony's proprietary Memory Stick.
These days, Sony offers a substantial variety of different digital cameras, perhaps more so than anyone else. Sony, always famous for its ability to miniaturize electronics better than anyone, has come up with some of the most impossibly thin designs, as well as some that are so chock full of features that it takes weeks to learn them all.
Sony currently differentiates its products as "full-featured," "point & shoot," and "ultra compact."
The "full-featured" line includes a number of standard size models usually with laarge optical zooms (up to 12X), but also the whimsical DSC-M2 with an unusual flip-design and MPEG 4 movie making capabilities.
The "point & shoot" class includes a number of very compact and very competent 6 to 8 mgapixel cameras with external zooms and both boxy and rounded body styles.
The "ultra-compacts" should really be called the "ultra-slims" because in that arena no one can touch Sony's T series. Some of those cameras are barely more than a third of an inch thick even though they have internal optical zooms. A new addition is the DSC-N1 that has an external zoom, but 8.1 megapixel and a large 3-inch display.