About 500 websites were expected to black out next week to protest the Federal Government's introduction of mandatory ISP-level filtering.
Electronic Frontiers Australia spokesman Colin Jacobs said more websites were joining the action.
High-profile participants in the online campaign would be revealed on Monday, he said.
But internet forum site Whirlpool would not be one of them, said founder Simon Wright.
"Officially, we remain apolitical on the matter and, for now, will limit our involvement to getting accurate information out there," Wright said.
It appeared that Australia Day protest BBQs would not go ahead, at least as publicly as the blackout website suggested.
"The idea was for smaller gatherings and outreach. It wasn't for mass events," Jacobs said.
"Quite a few people are holding individual events."
Only the Stop Internet Censorship campaigners in Brisbane publicly confirmed a location.
"We'll have a few sausages and some bread and sauce at the BBQ, but bring your own drinks and most of your own food," the group said.
National protests against the internet filters were planned for March 6.
For the latest on the EFA blackout click here.