Use this plugin: http://wordpress.org/extend/plugins/wp-hide-post/
For hiding author and date you have to edit your theme.
Edit# that plugin does that allready, but i think its better to just do those small edits and not add load to your site.
<?php _e('Posted on',sa); ?> <?php the_time('d. M, Y'); ?> <?php _e('by',sa); ?> <?php the_author_posts_link(); ?> <?php _e('in',sa); ?>
1. edit: index.php or home.php (Main index template)
2. find <?php the_content(); ?> or <?php the_excerpt(); ?>
3. Remove it.
4. yey done!
removing it has nothing to do with css if u wanna hide try text-indent )
<!--
<?php the_content(); ?>
-->
or
<!--
<?php the_exceprt(); ?>
-->