Can someone tell me what wordpress plugin this is on the bottom right of the page? It basically pops into view when you get to a certain portion of the page. You can see an example of it in action if you go to this article and scroll all the way down http://mashable.com/2011/11/20/muppets-social-campaign/ Anyone know what it's called?
I had used "upPrev Previous Post Animated Notification" plugin on one of my website. I used to display the posts from the same category. Maybe it can show the next posts as well. You will have to check the settings.
most of their plugins are custom, but you can get similar features in "Digg digg" and "sharethis" Hope it helps
I don't think this is custom. People.com and plenty of the other large media publishers have this on their site as well.
Possible, but large companies do not hesitate to customize even the popular plugins to make it look somewhat unique. When you install Dig dig/shareit, it will look similar but not the same. It is also possible that I missed something, but still they have many other custom made features for their wordpress website.