Staying Fresh on Facebook

I swear half the articles I read on Ad Age these days are about facebook. The following article talks about the numbers behind how long posts and comments on news feeds last.
http://adage.com/article/digital/facebook-s-news-feed-a-limited-engagement-advertisers/227151/

The takeaway:

• To maximize your exposure, you should post every hour and twenty minutes.
• To get 95% of your fans to see a post you only need to leave it up for 22 hours. Don't put back to back posts to close to each other because your new posts will cannibalize the interaction of the older posts.
• Posts on facebook have a longer shelf-life than twitter, as 95% of all retweets happen within an hour.