Largely under-utilised by marketers, landing pages are an indispensable tool at the core of every inbound marketer's lead generation efforts. A good landing page will target a particular audience, and get them to download a content offer (eBooks, white papers, webinars, etc.) or even redeem other marketing offers like deals, free trials, etc.
The great thing about landing pages is that by targeting your audience and offering them something of value, you'll capture information about who they are and what they've converted on!