These aren't wide portals, such as Yahoo or Excite, but, rather, well known sites within a narrow advertising segment. Category killers combine extensive product listings with detailed information about the products. They often have tools and applications for helping users, and will have e-commerce capabilities to help clients make transactions. These sites are also more likely to target display advertisers, which represent the majority of classified revenue. There are demonstrable benefits to advertising on the Net.
Turnaround time is also a factor.
People are at a premium and time is of the essence, and the Net is proven to speed the hire. It's tough to say. And anecdotal evidence suggests that the trend is up indeed. The staffing firms we spoke with are focusing on Net classifieds for a variety of reasons. For some, it's only logical.