A cross-sectional design has often been used to study the quality of health-related educational materials meant for lay adults (e.g., patients, the public). The present study addressed this research limitation. We documented the proportion of online physical activity promotion (PAP) material revised within a given time period and how quality was affected, if at all. PAP web articles (N = 139) meant for lay adults, written in English, and first sampled in July 2018, were resampled in July 2020. Mean publication year at timepoint 1 was 2016.82 (±1.24). At timepoint 2 it was 2018.78 (±1.39). At both timepoints, suitability for lay use was appraised using five dimensions of the suitability assessment of materials (SAM) protocol: i.e., content, literacy demand, graphics, layout and typography, and learning stimulation/motivation. There were 61 web articles (43.9%) with indicated revision and analyzed in the present study. Articles were distributed across four organizational subgroups: commercial (n = 21), government (n = 13), professional association (n = 10), and voluntary health agency (n = 17). In the aggregate sample, two SAM dimensions significantly improved: literacy demand (e.g., more active voice) and layout & typography (e.g., formatting). Often, organizational subgroups mirrored the aggregate sample. Although the overall suitability remained within the satisfactory range across the dimensions, a moderate-to-large number of articles remained unsatisfactory at timepoint 2 within several subdomains (e.g., reading grade level, summary section). This study’s findings further evidence PAP materials are somewhat suitable and the need to study suitability subdomains in addition to overall suitability.