For viral you need to do some interesting things. If you provide any content on any website make it as funny as you can.
Write a great resource page in your niche. Users will link to you as they value your contents. You will get viral attention from Google.
When you post, find what people are talking about the most RIGHT NOW. Using Google keyword tool is great to know what people have been talking about over the last 12 months, but get an edge by finding the newest topics in your niche. Can you think of a few tools that help demonstrate what people are talking about RIGHT NOW? This helps me.
create information that people want to share...the one certain thing is that you DONT get viral attention from Google...Google give YOU attention from getting viral attention from your USERS. focus everything on your users and you will be ok in Google's eyes.
if you've got this exclusive news or something really interesting what could capture human attention, these sites would do it for you!