It's common knowledge at this point that quote unquote "hipsters" love most things with a vintage feel. Suspenders, bicycles, impractical moustache designs -- all of it's fair game. So it isn't the worst idea in the world to try and make your old junk sound chic when you're selling it online.
Take this Craigslist ad, for instance.
Sure, you could admit that the computer is almost 20 years old and probably runs incredibly slow with only enough memory for some text files -- but why do that when you can pitch it as the coolest alternative to an iPad?