According to the "LITA Standards Task Force White Paper," the most important standard for library technology workers is the MARC / MARCXML standard. This finding comes from a survey distributed to the Library Information Technology Association (LITA) members last September and October. According to LITA,

A brief survey of 14 questions was drafted and sent out to the LITA membership. In the survey, questions were organized into three categories:  1) standards use; 2) standards creation and participation; and 3) interests and future directions. 

The survey was open for two weeks (9/24/10 -10/8/10) and a total of 230 responses were received, a response from roughly 9% of the LITA membership. According to LITA survey records, the response rate was very good.

The results from question 3 on the survey (displayed below) show the importance of the MARC standard. It is notable that the survey targeted members of a library technology association and not library staff necessarily involved in cataloging or library technical services.

More notable is the absence of Semantic Web standards from the answers to this particular question. Notice that SKOS, RDF, and SPARQL do not even appear in the "other" section of the survey response (see below).

Respondents who selected "other" for this question typed in these responses:

AACR2 (4)

AAT

AES-X098B (technical audio metadata)

ANSI/NISO

ARK identifiers, JHOVE metadata etc.

CORE

COSATI

COUNTER (5)

DDI3

Digital imaging standards, digital preservation standards, user authentication standards

EDI

FRBR

Homemade standards/In House Rules and Tools (2)

ILS-DI

Information literacy standards and educational technology standards

Interoperability standards

ISBN, ISSN, ISRC, ISMN, SICI, EAN, UPC

JSON

LCC (2)

LCRI,

LCSH (2)

MADS

NCIP (8)

NewsML, PB Core

None (7)

OAI-PMH (3)

ONIX, ONIX-PL

OpenURL specification (4)

PCI (Payment card industry standards)

PMI Standards

RDA (6)

Rules for Archival Description

Section 508

SERU

SIP2 / SIP (4)

Statistics

SUSHI (3)

TEI

textMD, copyrightMD, MADS, documentMD, CCO, CDWALite, FGDC, DACS

VRA4 / VRA CORE / VRA (5)

WCAG

Z39.71

Z39.86-2005

Overall this survey provides a fascinating snapshot of the standards currently of importance in libraries. MARC survives because it fills a central library function and despite the many attempts to end its use (e.g. Scriblio, which isn't among the responses). The absence of Semantic Web standards among the several dozen responses to question 3 is very telling.