As expected for a database upgrade Twitter is down. According to the official twitter blog - We’re planning a significant database upgrade that will greatly increase system performance. To do this, we will require two planned maintenance windows: Friday, May 8th from 2p-3p Pacific and again on Monday, May 11th from Noon-1p Pacific.
We’re taking these maintenance windows earlier in the day because of the extent of the changes involved. We want to make sure that we are able to respond quickly and efficiently to any issues that may arise from the work being performed.
We will update here with any changes or additional information about this upgrade.
Update (2:00p): Today’s maintenance window is about to commence. During this time, and the subsequent window on Monday, all Twitter services will be unavailable.