I just saw an ad for Comcast high speed internet, the service I (reluctantly) use. All the computers shown in the ad are Macs – an iMac, a PowerBook, etc.
But Comcast doesn’t support Macs. (Well, because a Mac speaks all the languages it needs to, you can use Comcast internet service. But when you click on “Customer Support” on their service home page, you get a big black window with a terse “MAC NOT SUPPORTED” message.)