Personally, I like a mix of facts, list format, and humour. I read Cracked a lot, and they have valid and well-sourced information, but they also use an easily readable format with the lists, which I find helps a lot in making an article simple to understand and digest in bite-sized chunks, which I'd rather read than a wall of text (the exact reason why I've occasionally skimmed over threads or articles on this very site

). But the humour is important too, to encourage people to read it.
I would recommend looking at the work of some successful internet writers, includind the Cracked team (as they mostly have their own sites or sidelines in writing non-Cracked work too) and use those for inspiration. Take particular note to Seanbaby, Dan O'Brien, and Christina H for examples of really good writing. Also, any homage to Charlie Brooker gets extra points in my book xD.