I was setting up a demonstration event web site to show how events can become more social. I setup new accounts for the event at Facebook, Twitter, and LinkedIn.
Facebook has their Fanbox
tool that easily allows you to build a widget or badge to showcase your Facebook page on your web site.
Twitter has their profile widget
that quickly puts your Twitter stream on your web site.
LinkedIn just has their promote your profile buttons.
Facebook and Twitter gives you ready to go tools for building an advanced widget that extends your profile beyond their network and onto your web site. LinkedIn just gives you buttons? They need to step up with some better tools.
Ok...guess I didn't look hard enough. They have a selection of widgets at - http://developer.linkedin.com/community/widgets