Is Google under any real threat from competitors? Sure does not sound that way when you look closer at where things are at. Despite the fact that Bing, Facebook and Twitter getting into the search game, Google remains king of the jungle.
To date, the only real threat to Google would be Bing…a few years down the road. Facebook and Twitter however, are great for spotting trends but are not going to be real helpful in the transitional search world.
As for how advertising will do as each of these search sources continue to grow, it’s going to be battle royal as competition heats up. Lesser properties such as Yahoo, Dogpile, Altavista among others will likely continue wear down a the bigger kids continue to take up the advertising sources from everyone else.