We're in the BtoB arena so what's working for us are webinars (custom for an advertiser; and editorial-based which are sponsorable) -- very profitable. Sponsor gets logo, mention, inclusion in all audience promotion activities, and the registration list. It's a great value for them; online directories -- products and services, with paid listing upgrades. Buyers can purchase bite-sized upgrades to increase their visibility or depth of information; online "channels" (think cable TV-type channels -- fishing, sports, news, history -- applied to your market). Advertisers sponsor a content or subject "channel" where the magazine places related content, and the advertiser can post white papers, collateral materials, etc. -- they pay an annual fee and it is category exclusive. The key, of course, is ensuring that you're driving traffic and audience. Advertisers are becoming more sophisticated and demanding about metrics, so often traffic alone isn't good enough -- they want click thrus, uniques, # of page views, etc.
Commercial Use Limitations: Use of any content features (blogs, forums, messaging, etc) for direct self-promotion, spamming, etc. will result in account termination. Profiles are for individuals only at this time, not companies. Profile headshots should not include company logos. Publishing/Media companies (non vendors) may create groups for their employees. Vendors see this post for more information.