Mark discusses what elements you should have in your lead capture form.
On any given landing page, the lead-capture form is the most crucial element. Without the form, lead generation simply wouldn’t be possible.
Therefore, the form is the main focus of your landing page, since the ultimate goal is to get your visitors to complete it.
Read more from Hubspot: http://blog.hubspot.com/blog/tabid/6307/bid/28472/The-5-Critical-Components-of-Fantastic-Lead-Capture-Forms.aspx