@UlrikeHahn Well, I'd think if anyone follows, or boosts, or likes your content, then it is out there... plus there are relays that boost content from many Fediverse server public feeds, etc.
This doesn't count intentional "scraping" of all public fediverse posts that clearly is also happening. For example even with search indexing marked as "off" on our server, see this:
https://www.google.com/search?q=%40tchambers%40indieweb.social&sca_esv=e1291adcbee06b02&sca_upv=1&source=hp&ei=ljAQZrn2FJjl5NoPw4cm&iflsig=ANes7DEAAAAAZhA-poo7ekCzmuxLDAqodmpRmX5PMTMs&ved=0ahUKEwi5mYjLyKuFAxWYMlkFHcODCQAQ4dUDCBc&uact=5&oq=%40tchambers%40indieweb.social&gs_lp=Egdnd3Mtd2l6IhpAdGNoYW1iZXJzQGluZGlld2ViLnNvY2lhbEiZY1CRAlj4YHAXeACQAQKYAegCoAHTH6oBCDQ2LjMuMC4xuAEDyAEA-AEBmAI2oAK_F6gCCsICEBAAGAMYjwEY5QIY6gIYjAPCAgsQABiABBixAxiDAcICDhAuGIAEGLEDGMcBGNEDwgIREC4YgAQYsQMYgwEYxwEY0QPCAgsQLhiABBjHARjRA8ICCBAAGIAEGLEDwgIOEAAYgAQYigUYsQMYgwHCAggQLhiABBixA8ICExAAGIAEGIoFGLEDGIMBGEYY-QHCAhEQLhiABBiKBRixAxiDARjUAsICBRAAGIAEwgILEC4YgAQYsQMYgwHCAgQQABgDwgIOEC4YgAQYigUYsQMYgwHCAgUQLhiABMICBBAAGB7CAgYQABgeGArCAgYQLhgeGArCAgYQABgIGB7CAgkQABgeGMkDGArCAgsQABiABBiKBRiSA8ICCBAAGAUYHhgKwgIIEC4YBRgeGArCAgoQABgFGB4YDxgKwgIGEAAYBRgewgIIEAAYgAQYogSYAwSSBwQ1MS4zoAfbkgI&sclient=gws-wiz#ip=1