Dax Hamman posted an interesting article on the e-consultancy blog in which he talks about how email marketing fits in a Web 2.0 world. This is what he concludes:
"Email was crucial in the Web 1.0 value chain. For example, the marketer would decide what product was "on offer" that week and push out email offers to the opt-in email list. Or, the marketer would use the website navigation hierarchy to drive purchase (e.g. promotions on the home page). Product relevance to the target email list was not necessarily high, it was simply what was being promoted that week.
In the Web 2.0 value chain, the consumer decides which products are most interesting to them through keyword searches or blog recommendations. The purchase is then initiated from deep inside a website - where the search navigation drops the user - and hierarchical web site navigation (i.e. starting on the home page) is ignored. If the shopping process is abandoned, remarketing emails can push a consumer over the finish line. Therefore email closes the "search loop." Other places a marketer can use email is to encourage a customer to retrieve forgotten shopping bags, or share wish lists with family and friends.
So it's not that email is no longer relevant in a Web 2.0 world, quite the contrary. It's simply shifted position… which might be interpreted by some as a demotion. However, the better way to look at it is that email now completes the conversation, or prolongs the marketer/consumer dialogue, rather than starting it."