While browsing a biographical entry in Wikipedia earlier this afternoon there was a message that the English (language version, presumably) is being blocked by the editors in a few hours time, seemingly indefinitely, as a protest against two pending pieces of US legislation which they claim would restriuct freedom of expression. I surmise that this will be around or soon after midnight GMT.
The closing sentence of the BBC News report on this states: "Sites taking part in the shutdown plan to go offline for 24 hours from midnight Eastern Standard Time (05:00 GMT) on Wednesday."
I also use Wikipedia for its biographies, along with its articles on historical events which can help to put a person's or a family's life into into historical context. Hopefully the site will be up and running again on Thursday.
Steve