title: put labels to ggplot2 graphs
body: <p>I am trying to add labels to <strong>ggplot2</strong> graphs that have many points and lines using <code>geom_line</code>. Since the graph has way too many data points and linear lines, it looks very cluttered. </p>
  
  <p>I would like to add lables to the linear lines so that end user will definetely know what lines belongs to what server etc. </p>
  
  <p>my data frame looks like this</p>
  
  <pre><code>&gt; z
  Hostname    Memory  Date
  ServerA         50  2012-01-01 01:00:00
  ServerB         30  2012-01-01 01:00:00
  ServerC         30  2012-01-01 01:00:00
  ServerD         20  2012-01-01 01:00:00
  ServerE         80  2012-01-01 01:00:00
  
  ServerA         20  2012-01-02 01:00:00
  ServerB         10  2012-01-02 01:00:00
  ServerC         5   2012-01-02 01:00:00
  ServerD         39  2012-01-02 01:00:00
  ServerE         50  2012-01-02 01:00:00
  
  
  
  p &lt;- ggplot(z, aes(x=Date, y=Memory, colour=Hostname, size=0.1)) + 
          geom_point(size=0.1) + theme_bw
  
  () + geom_smooth(method = "lm", se=FALSE, size = 1) + 
           theme_bw() + geom_point(size=0.2)
  </code></pre>
  
  <p>I tried using <code>direct.label(p, "last.points")</code> or <code>first.points</code>, but it is still not clear enough. And when I do last.points, labels are being chopped off.</p>
  
  <p>Is it possible to put a lable on the <code>lm</code> line?</p>