Google makes billions from pushing brief text ads to Web sites.
Ever wonder why text, and not pretty pictures and pulsating colors, like many of the banner ads from non-Google sources?
Text is highly efficient. It lets Google push millions of ads with far less computing overhead and through thinner networking pipes than is needed with image-based ads -- whether animated GIFs or heavyduty Flash. Conversely, Google can ship many, many more ads through the same Internet facilities than can proponents of fat ads.
(Also, text ads are less annoying to users than dancing icons. And, the brevity of the text ads makes them more likely to be read.)
I wonder if the founders learned that from the travel industry. Many travel agents use plain terminals that show green text on black background; even Canada's largest electronics chain, FutureShop, continues to use such terminals. The reason: extremely efficient network operations. It takes very little to push characters of text. If it costs less, then there are higher profits to be had.
Here's how efficient: think back to the original PalmPilot 1000. It had just 0.1MB of RAM, yet could hold thousands of addresses, appointments, et al.
Contrast that with MP3 music files. 0.1MB is enough memory for six seconds of music. Or highly compressed, low resolution video: 0.1MB is sufficient for one second of video.
Whereas Bill Gates instructed his programmers to assume infinite computing resources, the Google "brothers" assume infinite customers, combined with the realpolitik of limited computing resources.