From Steve Champeon comes the

From Steve Champeon comes the evolution of the portal:

1) come here
2) go somewhere else

became

1) come here
2) look at an ad (ka-ching!)
3) go somewhere else

became

1) come here
2) look at an ad (ka-ching!)
3) go somewhere else, but stay on this site
4) goto #2

becomes

1) come here
2) go somewhere else, but stay on this site
3) buy something (ka-ching!)
4) goto #2

AOL has been so successful, perhaps, because they skipped right to the last part.