edit content.php and remove this section

            <?php if ( 'post' == get_post_type() ) : ?>
            <div class="entry-meta">
                <?php twentyeleven_posted_on(); ?>
            </div><!-- .entry-meta -->
            <?php endif; ?>

            <?php if ( comments_open() && ! post_password_required() ) : ?>
            <div class="comments-link">
                <?php comments_popup_link( '<span class="leave-reply">' . __( 'Reply', 'twentyeleven' ) . '</span>', _x( '1', 'comments number', 'twentyeleven' ), _x( '%', 'comments number', 'twentyeleven' ) ); ?>
            </div>
            <?php endif; ?>

and this section

        <footer class="entry-meta">
            <?php $show_sep = false; ?>
            <?php if ( 'post' == get_post_type() ) : // Hide category and tag text for pages on Search ?>
            <?php
                /* translators: used between list items, there is a space after the comma */
                $categories_list = get_the_category_list( __( ', ', 'twentyeleven' ) );
                if ( $categories_list ):
            ?>
            <span class="cat-links">
                <?php printf( __( '<span class="%1$s">Posted in</span> %2$s', 'twentyeleven' ), 'entry-utility-prep entry-utility-prep-cat-links', $categories_list );
                $show_sep = true; ?>
            </span>
            <?php endif; // End if categories ?>
            <?php
                /* translators: used between list items, there is a space after the comma */
                $tags_list = get_the_tag_list( '', __( ', ', 'twentyeleven' ) );
                if ( $tags_list ):
                if ( $show_sep ) : ?>
            <span class="sep"> | </span>
                <?php endif; // End if $show_sep ?>
            <span class="tag-links">
                <?php printf( __( '<span class="%1$s">Tagged</span> %2$s', 'twentyeleven' ), 'entry-utility-prep entry-utility-prep-tag-links', $tags_list );
                $show_sep = true; ?>
            </span>
            <?php endif; // End if $tags_list ?>
            <?php endif; // End if 'post' == get_post_type() ?>

            <?php if ( comments_open() ) : ?>
            <?php if ( $show_sep ) : ?>
            <span class="sep"> | </span>
            <?php endif; // End if $show_sep ?>
            <span class="comments-link"><?php comments_popup_link( '<span class="leave-reply">' . __( 'Leave a reply', 'twentyeleven' ) . '</span>', __( '<b>1</b> Reply', 'twentyeleven' ), __( '<b>%</b> Replies', 'twentyeleven' ) ); ?></span>
            <?php endif; // End if comments_open() ?>

            <?php edit_post_link( __( 'Edit', 'twentyeleven' ), '<span class="edit-link">', '</span>' ); ?>
        </footer><!-- #entry-meta -->

or part of the above...