What is the best marketing strategy for a new internet startup ?

These are the general strategies that should form the foundation for the marketing:

Understand what customers you will focus on and which ones you will ignore.
Understand what problem you will solve or what need you will serve better than anyone else.
Understand how you will make money: how much you will make from each customer, how many customers per month you need, what marketing you need to get those customers, what activities and budget is required.
Build a better product and then tell your story in a way that is clear, simple, differentiated, interesting and compelling.
Execute.
Let your customers become your best marketers.
Optimize.