Update1: It's not the 2nd time Facebook went down. According to ABC news Facebook went down yestrday also, due to Facebook Applications.
Update2: Facebook’s Platform status page says:-
We are currently experiencing latency issues with the API, and we are actively investigating. We will provide an update when either the issue is resolved or we have an ETA for resolution.
Update3: Here’s the statement from Facebook:
We’re currently experiencing some site issues causing Facebook to be slow or unavailable for some users. We are working to resolve this issue as quickly as possible.
Update4: By the time Facebook is down you can read and do these stuffs, to read Click here.
Update5: Mashable says:
AlertSite notes via e-mail that, “Facebook started experiencing problems at around 2:30 PM EST. Between 2:30 PM EST and 3:30 PM EST Facebook only had 38.46% availability with sky high response times of up to 60 seconds reported from one of our monitoring locations. Over the last hour, AlertSite has recorded errors in all 12 of its monitoring locations throughout the US.”
Update6: Facebook is now seems to be restored and working fine after 2 and a half hours.