Online Proofing Software segmentation by application maps functional use cases to end‑user industries. In advertising and marketing, proofing platforms accelerate campaign approval cycles, supporting rapid creative iteration and cross‑regional stakeholder sign‑off; this segment commands the largest share due to high volume of assets. Publishing and media rely on proofing for editorial workflows, page layout validation, and rights management, representing a significant but lower proportion. Architecture, engineering, and construction (AEC) employ proofing to review technical drawings, BIM models, and compliance documents, a niche with stringent revision control. Manufacturing and product design use proofing for prototype visualisation, design change approvals, and supplier collaboration, contributing a growing share as digital twins proliferate. Education and training institutions adopt proofing for curriculum material review and collaborative project assessment, a modest segment. The pie‑chart data below quantifies these contributions, reflecting the current market taxonomy where advertising & marketing accounts for 45 %, publishing & media 25 %, AEC 15 %, manufacturing & product design 10 %, and education & training 5 % of the overall market.