This question gets asked at least 5 times a year.

We are an inclusive bunch - post what you want, people will respond if they chose. Generally speaking, this group has a lot of different kinds of members...some of us are more iconoclasts based around similar definitions to what the CR list uses. Some like cheap old bikes because, well, they're cheap. Interests vary across country of origin and components.

The CR list definition is 1983, light weight, steel. Some bikes of a later age are designated keeper of the flame.

It's subjective...and the forum includes classic, not just vintage.

Common definitions of vintage are:

20 years old
25 years old
up through 1983 (C/R list definition) , when many changes happened at once

Classic means different things to different people - to me it means bikes that are especially beautiful, influential or desired. There are CF bikes I consider classic and most vintage bikes aren't classic to me - they're just old. The bikes people like best here are usually the ones that are both classic AND vintage - like a 1970s De Rosa, or a Rene Herse.