
However, medium is a powerful way of engaging the people and they spend a great deal of time talking about brands and products online. They tweet about it, complain on facebook, write on mouthshut, recommend on linkedin and so on. Putting this behaviour of the customer of ignoring the messaging on one hand and yet talking about brands, into a single cohesive framework, is pretty difficult. Yet I will give an attempt, by revisiting some of the marketing fundamentals. So let me call into action the concept of "buying decision process" to bring in clarity. For a quick recap, I am putting up the diagram that explains the three phases of buying process.

The first stage is the most critical in my opinion. As marketers we know that "needs" cannot be created per se. But latent needs can be made active and that's what successful marketing efforts are supposed to do. Here web 2 can play the role of information gathering, awareness building and initial branding. In "Information Search" phase, people are increasingly resorting to web 2.0 measures like mouthsut, compareindia etc to seek info and get second opinions from strangers and friends. So in a way web 2 is the most effective during this stage of buying.
"Evaluation of Alternatives" is a complicated phase. Much of it I assume happens as an internal process to the customer, but the information he has gathered can impact the evaluation. "Purchase", what and when, can be influenced through web 2, in as a direct recommendation from the friends community on Facebook, etc. Post purchase is of course a whole lot dependent on the quality of products or services consumed. But web 2 can definitely help reduce some dissatisfaction if there is any. Like for example, if most users are already comfortable with the performance of the product in the way it is and write about it, then the customer may get reconciled with his frustration.
Thus we can see that web 2 holds varying influence in all the stages. This again will vary depending on the levels of involvement for each product. It is needless to say that there is no definitive conclusion, except that "intelligent discretion" is the only way out.