Google was a huge success by the time it went out of beta. I think this was late 1999.
By 2004's IPO Google's success would be considered "the standard by which success will be defined for the next 20 years" type of huge success rather than merely another run-of-the-mill Silicon Valley $100M exit type of huge success.
By what metric was it a huge success in 1999? They had a good product, but most people had never heard of the company. I remember having to explain that it was "kind of like Yahoo, but with good search and none of the other features", and they were always like, "well, good luck with that." (obviously thinking to themselves, "another stupid .com")
I wonder if Google realised before adwords started growing like wildfire that search was such a potentially powerful advertising platform.
I know that other pay per click & search marketing services were around and were reasonably successful, but a lot of that was probably hard to seperate from the bubble. I mean I don't think there were many plumbers advertising on search in 99' & coca cola was never going to work.