17. A method for recommending job recall activities to a user of an online education platform, the method comprising: extracting learning units, by an automated learning units extraction system of an online education platform, from content stored on a platform content catalog database of the online education platform, the extracting comprising: performing text extraction on the content to extract sequences of glyphs and embedded fonts; mapping the extracted sequences of glyphs and embedded fonts into character strings in a Unicode format; generating multilayered markup language documents from the character strings by aggregating content layers onto the character strings; identifying, from the multilayered markup language documents, content media types of the content comprising primary sources and secondary sources, the primary sources comprising one or more of a summary, a syllabus, and a textbook, the secondary sources comprising one or more of related content, user-generated content, Q&A, and testing materials, and sorting the content media types according to reliability of the content media types, wherein reliability of the primary sources is higher than reliability of secondary sources accessing user profile data of the user specifying learning units and job recall activities completed by the user, each job recall activity describing a user interaction with a job recall material; identifying by the online education platform, a set of available job postings based on learning units associated with each available job posting and the learning units completed by the user; determining by the online education platform, a recall gap between job recall activities associated with the available job postings and the job recall activities completed by the user, the recall gap comprising uncompleted job recall activities each mapped to at least one of the learning units in the learning units database; and recommending the uncompleted job recall activities to the user.
19. The method of claim 17 , wherein recommending the uncompleted job recall activities to the user comprises: identifying learning units not completed by the user mapped to the uncompleted job recall activities; recommending to the user, the learning units not completed by the user; and recommending the uncompleted by recall activities to the user.