Importance of "We would like to know how you found out about XXX college"

For questions such as “We would like to know how you found out about Brown! Please identify the option(s) from the list provided that were the most influential in your decision to apply.” does the response matter (it is selected from a drop-down list)? I would presume it is asked on the basis of statistic measures but I was slightly curious (I would not bother mentioning the friend’s name if it were only for statistics but may divulge if there were other significance).

Would filling/not filling in such questions affect admission chances at all? I submitted my Yale app without filling in a similar question… I hope I was right to assume that the question is only for statistics o.o

It doesn’t matter for the consideration of your application. The school uses the data to assess their marketing techniques.

Your assumption is correct.