NPR's Jim Zarroli reports the internet and related technologies are reshaping Wall Street. Just a few years ago, someone who wanted to buy stock had to go through a broker who charged a hefty fee for processing the trade. Now investors can go online to find the services and information brokers provided and they can do so for much less money. That's been a boon for investors, but it's forcing brokers to reassess how they do business. NPR's Jim Zarroli reports.