Another compromise has to do with the full-size spare tire, which goes missing in the Cayenne Diesel, displaced by the AdBlue reservoir (diesel models get a space-saver spare).

WSJ: 2013 Porsche Cayenne Diesel Review: Only Geeks Need Apply | Rumble Seat by Dan Neil

It was roughly the size of a large tractor tire.

NPR: Excerpt: 'Legends'

Users may tire of advertisements, particularly on their pocket-size smartphones where screen real estate is limited.

WSJ: Facebook Revenue Rises 40% as Mobile Ad Sales Strengthen