Kara Swisher: "the grand total who knew what Twitter was: 0 ... the intense obsession... the echo chamber of Silicon Valley, and how no one else cares yet."
Making a householdword is the great challenge. Not only does the word need to be universally known, but it has to be universally known for something that people need. eBay, Amazon, Google, and Craigslist are universally known, and people need what those words mean: People need to buy & sell & search in their everyday lives. SecondLife is known, but people don't need it; Flickr could be the word that means photography -- the Kodak of the 21st century -- but it's wide value prop is fuzzy, and my non-tech friends still send me their crappy Shutterfly links. I'm highly suspicious of most startups' potential to reach sustainable householdword status because they're not really serving real people's needs. As for Facebook, people need to stay in touch with people they know, so they're on-track, but I suspect their word is too muddied with pokes & kid stuff.
Someone needs to write the "Crossing the Chasm" for this era.