Is it a blackout or a lockout?
The mobile version of the site is still available. People were able to view pages on Wikipedia if they turned Javascript off. Beyond that, there was routine admin work being doing by sysops. This was non-emergency work, that could have been done BEFORE or AFTER the lockout. Examples:
17:35 (Deletion log) . . [28bytes; Ryan Kaldari; Fetchcomms; Eagles247 (2×); Nyttend (5×); Fastily (13×)]
17:35 . . 28bytes (talk | contribs) changed revision visibility of "I'm Not the One": restored content for 1 revision (RD6: Non-contentious housekeeping, RevDel corrections, notes, conversion: restore 1 revision w/o copyright issues) 17:34 . . Nyttend (talk | contribs) changed revision visibility of "Logan Hayes": removed content for 340 revisions (RD1: Blatant copyright violations) 17:29 . . Nyttend (talk | contribs) changed revision visibility of "Logan Hayes": removed content for 266 revisions (RD1: Blatant copyright violations: A pity the developers haven't given us an Invert option; it would make things substantially quicker) 17:24 . . Nyttend (talk | contribs) changed revision visibility of "Logan Hayes": removed content for 172 revisions (RD1: Blatant copyright violations) 17:13 . . Nyttend (talk | contribs) changed the visibility of one or more entries in the (Deletion log): restored username for 1 entry (Test complete) 17:12 . . Nyttend (talk | contribs) changed the visibility of one or more entries in the (Deletion log): removed username for 1 entry (Is it possible to do RevDel when Wikipedia is engaging in blatant WP:POINT violations?) 16:32 . . Fetchcomms (talk | contribs) changed revision visibility of "City Colleges of Chicago": removed content for 1 revision (RD1: Blatant copyright violations) 16:30 . . Eagles247 (talk | contribs) changed revision visibility of "Paul Ryan (As the World Turns)": removed content for 9 revisions (RD1: Blatant copyright violations) 16:25 . . Eagles247 (talk | contribs) changed revision visibility of "Nadine Crowell": removed content for 154 revisions (RD1: Blatant copyright violations) 16:23 . . Ryan Kaldari (talk | contribs) deleted "MediaWiki:Centralnotice-blackout-wp-sopa-zipform-invalid" (no longer needed) 15:59 . . Fastily (talk | contribs) deleted "Template:Cite pmid/19334934" (G8: Redirect to a deleted or non-existent page) 15:59 . . Fastily (talk | contribs) deleted "Template:Cite pmid/18823098" (G8: Redirect to a deleted or non-existent page) 15:59 . . Fastily (talk | contribs) deleted "Talk:United heads" (G8: Redirect to a deleted or non-existent page) 15:59 . . Fastily (talk | contribs) deleted "Talk:Nicol rodriguez" (G8: Redirect to a deleted or non-existent page) 15:59 . . Fastily (talk | contribs) deleted "Talk:Andrew demcak" (G8: Redirect to a deleted or non-existent page) 15:59 . . Fastily (talk | contribs) deleted "Arthur Oscar Moritz Lindauer" (G8: Redirect to a deleted or non-existent page) 15:59 . . Fastily (talk | contribs) deleted "ISpyStrangers" (G8: Redirect to a deleted or non-existent page) 15:59 . . Fastily (talk | contribs) deleted "ISPYSTRANGERS" (G8: Redirect to a deleted or non-existent page) 15:59 . . Fastily (talk | contribs) deleted "Ispystrangers" (G8: Redirect to a deleted or non-existent page) 15:59 . . Fastily (talk | contribs) deleted "Wikipedia talk:Articles for creation/Finnamore" (G8: Redirect to a deleted or non-existent page) 15:59 . . Fastily (talk | contribs) deleted "Festus kator inyon" (G8: Redirect to a deleted or non-existent page) 15:59 . . Fastily (talk | contribs) deleted "Talk:Iced Vovo" (G8: Redirect to a deleted or non-existent page) 15:59 . . Fastily (talk | contribs) deleted "United heads" (G8: Redirect to a deleted or non-existent page)
Ending Recent changes. Times are UTC+11.