Does Denny's have wifi?
Yes it has and the connection is provided by Cafe.com which is a wireless HotSpot provider. This helps even the late diners stay connected to the internet as Denny's is open 24 hours access to the internet is unlimited.
Not all of them do! I was at the Billings, MT Denny's on the 20th of June and there was no WIFI signal anywhere to grab hold of.