I’ll admit it I’m a sucker for retro ideas and visuals – who isn’t? I think retro works because we already have formed memories and events both positive or negative which are brought to the surface when we see, feel or taste something that is old school or slightly retro.
It’s nearly a form of ‘cheating’ to gain am emotional link quicker, or even instantly. This is something new and innovative design and positioning can’t achieve – just because it’s new.
To me retro is really powerful when a brand or business ‘deserves’ to go there. Especially when it has a history worth reminiscing about. Battler brand Atari did this successfully with the Flashback console which was launched 25 years after the 2600 seen below. 
Obviously this is much harder for a start up, although we can use it in graphics, design or attitude, especially if our brand or market segment lends itself to a retro play. Feel free to add examples to the comments.
Get retro!
Lots of restaurants are successful based on the retro look and feel also.
Fuddruckers is one.