A crucial step that can be done parallel to research since you employ similar tactics, IA is the foundation of how you present your product/service to the world in a way that your users understand. Card-sorting is one tactical process for sorting out your IA, where a user (existing customer or prospective customer) takes high-level concepts written on paper/stickies (or virtual via a card-sorting app) and puts them in categories that make sense to them - the result is a series of buckets that inform your site topology, navigation and taxonomy (a great little term stolen from the biology world). The basic way to think about IA is that your user needs a way to get from one ‘room’ to another in your site ‘house’, and they will want to use a methodology they understand already.