We've tried out four of them so far. They have their proverbial pros and cons, but overall, they're a good start in bringing more interactive content to the world's largest business social network. In order to add one, simply go the left side of your LinkedIn home page and click on the "applications" link, which will take you to the .

1. Presentation

Did you really crush that presentation you gave when you were on the road last week? Well, if your friends and colleagues missed it, they might ask you to e-mail it to them. Pretty soon, your email box fills up with .ppt attachments.

With Google's Presentation App for LinkedIn, you can respond to those inquiries with a URL directing colleagues and others to your LinkedIn profile, where your slideshows will be embedded for everyone to see. The app, which appears on screen as a YouTube-sized widget, has easy click-through arrows, and the ability to change to a full screen.

Not a huge Google Apps person? Not to worry, Redmond-lovers, Google Presentations allows you to upload Microsoft Office PowerPoint presentations no problem.