Seems like a lot of people are close or totally right, since you just asked what they have in common. They have many banal things in common, including never having been in most of our kitchens.
So apparently it’s not a simple question as your OP indicated, since you have a very specific commonality in mind and we don’t know what you are going for.
My guess is that they both wet their beds until they were 10.
Since people are getting frustrated here’s the answer in a spoiler box.
[spoiler]
Jerry Seinfeld’s bio mother is
Syrian
Steve Jobs bio father is Syrian [/spoiler]
worst spoiler box ever.
Job’s dad was Syrian, Seinfeld’s mom was Syrian.
Sorry, my comment was that I could read the spoiler box, so it wasn’t spoiler-boxing anything.
Note to self: Don’t try to spolier-box links.
Rats, the answer wasn’t there when I started looking…
Ha, ha, ha! Astro: 
I was going to ask if you had any other source for this than wikipedia, because I find open-source information unreliable, but then I came up with a better question.
Why on Earth would anybody care about this?
Note forum this factoid was posted in.
I like the monogram answer better.
Links can be spoiler-boxed if done properly.
What physical attribute do Uma Thurman and Paris Hilton have in common? It’s simple, there’s no need to be pedagogical about it.
Oh, I’ll grant you that it’s in the appropriate forum, but I don’t understand why anybody would do the following:
Read biography summaries of Steve Jobs and Jerry Seinfeld.
Note the the fact that each had a parent from Syria.
Find this interesting enough to open a thread about it on a general-discussion message board. (This is the step where I get lost.)
Actually bother to open the thread.
Uma Thurman and Paris Hilton? Both have wierd noses and are way too skinny.
Extremely loose pussies?
Hey, you hear things! 
astro
Please, for the next time, state that it is going to be an extremely mundane and pointless trivia question.
With all due respect, do you think anybody is going to bother to research an answer to your next question?
Actually I already knew the answer because
[Tommy Fla-nay-gan] … I know Uma Thurman and Paris Hilton quite well … yeah … and I’ve slept with them … several times … yeah that’s the ticket.
[/Tommy Fla-nay-gan]
I thought that was sort of assumed going in.
Don’t want to cause mental distress. The answer is
Both wear size 11 shoes.
astro
Thanks for providing the answer. I’ll sleep a lot better tonight … with Uma Thurman and Paris Hilton.
I didn’t mean to be so judgmental of your first trivia question but geez I wish the answer was a bit more interesting.
At least your second question is more interesting because I have a female foot fetish.