I didn't really mean the post was insignificant, just that it was as low impact as can be for such a giant company.

And I don't agree, one of the company's stated purposes is "incubating urban technologies". They aren't actively asking for any idea out there, but they clearly intend to interact with other startups and inventors at some point, and the only way to make that happen is to get your name out there.

And again, what is the downside? If there isn't any, then "because we wanted to" is a good enough reason.