First a question - are we talking about Compact Digital Cameras.
If so the description of how the viewfinders work in the page on Compact vs Digital cameras is wrong. In most compact digital cameras the viewfinder is a LCD, and it shows what the cameras sensor is seeing. In this it is like the old film SLR cameras - the viewfinder shows what the main lens is seeing, so there is no question of parallax creeping in.
The main problem with this approach is that in strong light the image in the LCD is "washed out" - in extreme cases to the point where you cant see the image at all. This problem did not exist in SLRs because you looked at the optical image through an eyepiece.
The DSLRs use the same approach as the old SLRs, but many of them also have LCDs.
There is another approach which is to have an electronic (digital) image which is viewed through an eyepiece.
I have a Fujifilm camera which I bought in preference to a similarly priced Nikon, mainly because it had the option of looking at the image on an LCD at the back, or by looking at the same image via an eyepiece. I was tired of battling with trying to compose photographs on a "washed out" LCD.