Case in point: I wrote a bunch of screen scrapers in Perl to pull historical price-chain info out of Yahoo finance. A few months ago, they stopped working because of the latency and timeouts of the Yahoo servers. It wasn't my bandwidth (industrial strength) or my servers (ditto). It was the buggy, stretched-past-breaking servers on the Yahoo side. I switched to Google Finance -- they have a similar price chain service -- and voila -- no more problems.