It's interesting that most web 2.0 services do not appear deep in any theoretical sense. In particular, 99% probably do not have anything that comes even close to the sophistication behind the PageRank algorithm.

But still, some web 2.0 services have become very popular.

It seems that if you do not have any sophisticated algorithms behind your approach, you can still succeed if you are the first to address a need (even if you do it in the most naive way imaginable) and you get sufficient publicity.

The vast majority of people could care less about sophisticated algorithms. The vast majority of people do not obsess over whether an approach is prone to spam.