What is the status quo for vCard support by common e-mail clients (Outlook, Gmail, Apple's mail thing)? From what I can tell Outlook's support is a bit backwards; it has its own "standards" for vCard, but I can't find anything that specifies what they are, or if they have changed in the last couple versions (2010, 2013, mac:2011) to be more standard.
The RFCs for v4.0 and v3.0 seem readily available, but if I want to go to the lowest common denominator, 2.1(?), I can't find that RFC (or was it pre-RFC?).
Version 2.1 came out before the IETF took over the vCard standard. You can find the spec here:
http://www.imc.org/pdi/vcard-21.rtf
My experience with parsing Outlook vCards has been that they generally stick to the standard. However, there is some quirkiness with how Outlook folds the lines of property values that use quoted-printable encoding.