What do you think about the size of space bars?
Vintage PC key boards can be found with space bars that almost covered the entire width under the alphanumeric area; over the years they were made smaller, first, down to 7u, later to 6.25, some more recent key boards got even 6u space bars, found mainly on Topre's. Under the argument of having more modifiers, some have advocated Japanese style bottom rows that have even smaller space bars, in sizes of 4u and even some smaller. With a different argument, some people have proposed that the space bar should be splitted, to allow one thumb to be use for other purpose, besides allowing to insert a space between words.
The availability of splitted keyboards and under the theory that they have better ergonomics has provided further reasons to have small thumb keys for the purpose of inserting spaces between our words.
In an slightly opposite direction, the proponents of using the space bar as a function key may require instead the larger space bars.
There are even some arguments related only with the aesthetic aspects of a keyboard that may support the idea of a "traditional" space bar; however, some people think that a "long" space bar is only a reminiscence of the typewriter era.
What do you think.