You might want to read this.
Cutting to the chase: Unless you opt out, all your public posts (in your journal and in communities) can be included in the Explore LJ feature.
Before you blow it off as "public is public" it might be good to consider that communities can't opt-out, only journals, so if you don't opt out you might bring a community that would prefer to stay out of the spotlight into it with your posts. I've chosen to be nice to the mods of communiites I'm part of and opted out so my posts can't be spotlighted and bring in trolls. Thankfully the majority of the communities I myself mod are all friends locked and therefore protected.
Cutting to the chase: Unless you opt out, all your public posts (in your journal and in communities) can be included in the Explore LJ feature.
Before you blow it off as "public is public" it might be good to consider that communities can't opt-out, only journals, so if you don't opt out you might bring a community that would prefer to stay out of the spotlight into it with your posts. I've chosen to be nice to the mods of communiites I'm part of and opted out so my posts can't be spotlighted and bring in trolls. Thankfully the majority of the communities I myself mod are all friends locked and therefore protected.