Jan Luca wrote:
I don't create a parser extension, but on special pages you output a text with $wgOut->addWiki( '<wikitext>' ); or $wgOut->addHtml( '<html text>' );
With special pages, the extension is creating the whole page and must feed all of the output. With tag and parser extensions, the extension is only handling a magic word and must return either wikitext to be further parsed or HTML to be directly embedded in the output.