NI application: What do they do with your SSN?

I just mailed my NI number application and in one section it asks (roughly, I don't have the application in front of me anymore):

"Have you contributed to the social security of another country?"

If yes, then "Which country?" and "Provide your identification number (if known)"

I went ahead and put in USA and my SSN.

The question is, what can they possibly do with the US SSN number? Can it somehow impact my SS in the US or here?

Thanks,