One of the most striking things about being a westerner in India is the aggressiveness of tenacity of touts or hawkers - people who approach you on the street wanting to sell something or provide a service.
Indians are very enterprising and given many of their situations, it's no surprise that they really want to do business. Unfortunately their methods do more to repel business than attract it for people like me. The touts are a lot like email spam, or as Sachi says, pop-up windows. We call it "sidewalk spam".
First, they are selling something you don't want or need and never asked for.
Second, their message is indescriminate -we often hear offers to shine our shoes, which are usually sandals.
Third, they will not take "no" or "nahin" for an answer, ever.
Fourth, they are inexhaustable. Behind each tout is a line waiting (or not) for their turn.
Fifth, they do not speak English very well.
Sixth, the majority have hidden agendas and their only goal is to extract a maximum amount of money, even through dishonest means.
Seventh, responding in any way only encourages them. Showing a bit of interest causes a feeding frenzy.
Eighth, they interfere with the messages you want to hear. Well meaning individuals are often lost in the melee.
Ninth, it is a numbers game. Their MO seems to be tenacity and bombardment. Sending the message repetitively to 1000s of people is how to get one to bite.
Tenth and finally, they are learning quickly. Recently I saw two interesting products from the touts
- Foreign newspapers including USA Today
- SD memory cards

This is a vast improvement over faux wood carved elephants, postcards and bracelets.

Unfortunately, like email spam, the ignorant and naive folks make the sidewalk spam business model work. So, the message here is to do your part to fight sidewalk spam - ignore it completely and hope that it goes away.