Nobody here actually consulted a dictionary? Fluther, I am disappoint.
Vintage adjective /ˈvintij/
1. Of, relating to, or denoting wine of high quality
* – vintage claret
2. Denoting something of high quality, esp. something from the past or characteristic of the best period of a person’s work
Old adjective /ōld/
older, comparative; oldest, superlative
1. Having lived for a long time; no longer young
* – the old man lay propped up on cushions
2. Made or built long ago
* – the old quarter of the town
3. Possessed or used for a long time
* – he gave his old clothes away
4. Having the characteristics or showing the signs of age
* – marble now so old that it has turned gray and chipped
5. Belonging only or chiefly to the past; former or previous
* – valuation under the old rating system was inexact
6. Used to refer to the first of two or more similar things
* – I was going to try to get my old job back
7. Dating from far back; long-established or known
* – we greet each other like old friends
* – I get sick of the same old routine
8. (of a form of a language) As used in former or earliest times
9. Of a specified age
* – he was fourteen years old
* – a seven-month-old baby
10. A person or animal of the age specified
* – a nineteen-year-old
11. Used to express affection, familiarity, or contempt
* – it gets the old adrenaline going
* – “Good old Mom,” she said
So it looks like vintage, by definition, means something old that is of high quality whereas old is just… old. Therefore, something vintage is necessarily old, but something old is not necessarily vintage. I think the colloquial use is a bit of a marketing ploy. The real question for me, is what the difference between retro and vintage is, at least colloquially.