another approach for typeclass examples here: http://skipoleschris.blogspot.com/2011/09/type-classes-and-bounds-in-scala.html

gistfile1.txt

trait Publishable[T] {
  def asWebMarkup(p: T): String
}

case class BlogPost(title: String, text: String)

implicit object BlogPostPublisher extends Publishable[BlogPost] {
  def asWebMarkup(p: BlogPost) =
     """|<h2>%s</h2>
        |<div>%s</div>""".stripMargin format(p title, p text)
}

object WebPublisher {
  def publish[T](p: T)(implicit publisher:Publishable[T]) = println(publisher.asWebMarkup(p))
}

val post = new BlogPost("Test", "This is a test post")
val web = WebPublisher.publish(post)