[rufibarbatus]

1. Brown (touristic) signs are still a bit rare here, but they're always bi- or tri- lingual. Most other road signs are pictorial and follow international standards. Street signs show the name of the street in big, readable type. That said, even São Paulo denizens get lost here pretty often (and Brazilians from other towns even more so).

2. Ads weren't that localized to begin with. Billboards usually advertised appliances, commodities, magazines... not nearby places of interest. So they could have been anywhere, really, they were just "visual pollution" really. (I suppose by saying this I'm confirming your hunch?)

Concerning #2 still: when the bill got passed, the government started selling advertising space in the back of buses and inside the metropolitan transport system (trains and stations). I'm not sure if this is on purpose, but these ads have usually been far more localised (relevant to the route of the vehicle or the vicinities of the stations) than the billboards they somewhat replaced.