Jeremy Herve on "[Plugin: Jetpack by WordPress.com] Facebook like box and Twitter feed gone."

Both the Like box and the Twitter feed are properly displayed on my end too:

http://i.wpne.ws/TKwJ
http://i.wpne.ws/TLYu

You might want to disable or configure any browser extensions that may block access to Twitter or FB, like AdBlock or DoNotTrackMe. If you do not use such extension, you'll want to look at your Anti Virus software. Some Anti Virus, like Avast, include options to block Social Media sites on your computer.

Let me know if it helps.