Now that we have your Attention and Interest we hope to have created a Desire that will lead to Action. Welcome to AIDA - a model in marketing that describes the stages a person goes through during the process leading to the purchase of a product or service.

AIDA is among a class of marketing models known as hierarchy of effects which imply that consumers move through a sequence of steps when making purchasing decisions. These steps can be thought of in two flavors: thinking and feeling stages leading to a behavioral stage, which is the conversion.

The four steps of AIDA are:

1. ATTENTION: The consumer first becomes aware of a product, product category, or brand through an advertisement.
2. INTEREST: The consumer develops an interest in the brand or product and their positioning, benefits, and other aspects.
3. DESIRE: The consumer has a positive or enthusiastic feeling about the product or brand
4. ACTION: The consumer takes action. This may be a purchase, a sign-up, comparative shopping, or the like. Typically measured as a conversion.

One of the drawbacks to the AIDA model is that it implies a fairly straightforward linear process from start to finish, but that fails to capture what can often be a complex journey to a purchase. 

There are multiple versions of the AIDA model. These other versions on the whole add a bit more granularity by introducing in-between steps, but the premise remains largely the same. The WIkipedia article is a great source for learning more about AIDI.