<p>Separating paragraphs with blank lines is easiest 
for readers to scan, but they can also be separated
by indenting their first lines. This is often used 
to take up less space, such as to save paper in print.</p>

<p>Writing that is intended to be edited, such as school
papers and rough drafts, uses both blank lines and 
indentation for separation. In finished works, combining 
both is considered redundant and amateurish.</p>

<p>In very old writing, paragraphs were separated with a 
special character: ¶, the <i>pilcrow</i>. Nowadays, this
is considered claustrophobic and hard to read.</p>

<p>How hard to read? See for yourself:
  <button data-toggle-text="Oh no! Switch back!">Use pilcrow for paragraphs</button>
</p>