Get flash to fully experience Pearltrees
When writing an email the two main choices that you have are to write the email in plain text or to use HTML. With plain text all you can place in the email itself is text and anything else must be an attachment. With HTML in your email you can format the text, incorporate images and do most of the same things in the email that you can do in a web page.
Designing an HTML email that renders consistently across the major email clients can be very time consuming.