From the Career News newsletter (sorry, no link):
In September 2007 there were 4,270,000 online advertised vacancies, an increase of 165,200 or 4 percent from the August 2007 level, according to The Conference Board Help-Wanted OnLine Data Series released October 1, 2007.
In September, 2,934,100 of the 4,270,000 unduplicated online advertised vacancies were new ads that did not appear in August, while the remainder are reposted ads from the previous month. Online advertised vacancies were up (17.5%) over the year (September’06 – September’07). There were 2.78 advertised vacancies online for every 100 persons in the labor force in September.
I suspect this information is illustrative of the migration from newspaper employment ads to online job board ads (obviously many newspapers offer online ads too). This thought is supported later on in the same newsletter:
Seventy percent of all job seekers reported using online ads to look for employment, according to a recent study by The Conference Board, a Non-partisan and not-for-profit leading business membership and research organization.
Among respondents who received a job offer, the largest percentage (38 percent) feels that their job offer resulted from their Internet search. About one-third attribute their job offer to networking with friends and colleagues (27 percent) and “other,” including employment agencies (30 percent). Newspapers were the least likely to be cited as the source of a job offer with 24 percent of respondents citing print ads.