Here’s an excellent article that breaks down the three different buying stages and the kind of content that prospects are looking for:
Early Stage Leads: They are trying gathering information about the problem they are facing and how (and if) they can put together a business plan to address their issue.
Mid-Stage Leads: They are trying to figure out if you can solve their problem. Do you address their issue and what proof do you have that you can do so successfully?
Late Stage Leads: They are in the solution comparison stage and want to see how you stack up against you competition.