Articles be sure and organize them by categories. Otherwise, it’ll be like trying to find a needle in a haystack. And its critical that they be SEO keyword-rich.
Web forums people love forums where they can discuss things, so give them a place to vent and have their little flame wars.
Polls people also love to be asked their opinions, so give them a place to express it, even if its just a multiple-choice poll.
Games a huge number of people love to play games.