i first thought it is by birth/or death date. some relation to "now" might make this more interesting, like the astronomy picture of the day. if there are two on the same day they could simply be shifted.
on the start page (http://www.giantsofit.org/) you will be redirected to the person of today. i just posted here the first person because the person of today (jack kilby) has no image.
or do you mean more something like to have the person show on on her/his birthday or day of death?
I think he means the date is of special interest to that person. ie, birthday, deathday, day they released the first version of programming language x, day they founded company y, day product z sold it's first million copies, etc. Or even keeping it topical such as with a new release of OS X you could have one of the core designers / developers of the first version of MacOS.
It would make the list much more interesting, but would be significantly harder to curate and would require you add some additional blurb to explain why that individual was chosen for that day of the year. So I can't blame you for going down the lower maintenance route of just compiling a random order list of influential figures.
There's something about "random" order that doesn't sit comfortably with someone like myself. I'd agree that some kind of connection to today's date, e.g. birthday, release date, etc. would be good. Or even something simple like making the entire list alphabetical or chronological (that would of course entail preparing the entire list in advance, but if you still want to take suggestions then those suggestions could be for next year's list).
or do you mean more something like to have the person show on on her/his birthday or day of death?