Consolidation never hurt in the Internet industry, but TMP Worldwide ( TMPW) shareholders still don't have a clear idea of how it will help. The operator of Monster.com, the largest employment site on the Internet, told analysts Monday morning that the rival it is acquiring, HotJobs.com ( HOTJ), would enable TMP to rule the online jobs category with a two-brand strategy. But executives at the acquisition-hungry TMP also said they hadn't quite figured out how they would keep the two brands from blurring into one another. The answer is a crucial one, because investors are betting that the richly valued TMP will one day become a cash cow in the online job-hunting market, which is nibbling away at traditional markets like newspaper employment classifieds. Yet because there's plenty of overlap of visitors to Monster.com and HotJobs.com, and a weak economy tempts employers to use one online site, TMP has to find a way for each brand's growth not to come at the expense of the other's. Both sites make money mostly from the fees they charge for running employer ads or offering access to resume databases.