From its inception, on December 4, 1920, the founders of the Histadrut, the General Workers' Union in Palestine, had aspirations above and beyond a trade union designed to protect the rights of its members. A major goal was to build an infrastructure for the Jewish settlement through its working communities, workers neighbourhoods and developing essential industries such as water, transportation, food, construction and immigrant absorption plans.
The heads of the Histadrut were aware of the need to recruit its members for these tasks. The communication media in the early years were limited. Only a few households had the means to purchase a newspaper or radio subscription. The poster affixed to billboards in the streets or workplaces was a means of reaching the widest audience - even beyond the members of the Histadrut. The Histadrut newspapers 'Davar' and 'Omer' also needed outdoor advertising to promote their distribution.
Source:
http://www.shamir-brothers.com/userfiles/file/Files%20uploaded%20by%20Uri/English%20version%20v2_1.pdf
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