In the early days of the web, it was thought that the web would hasten the downfall of the "interruption" model of advertising and be the catalyst for the rise of the "permission" model.
In other words, the old paradigm wherein your favorite TV show or radio program would be interrupted by advertising was supposed to die. A new paradigm would arise in which you would grant permission for brands you had deep feelings for to market to you, substantially via the web.
Or, as a cynical old bastard might say, suddenly we'd all be volunteering for advertising.
There has been some marginal success by a few "prom king" brands to take advantage of the "permission" model. However, even these brands have not abandoned the interruption model. They're still making spots. They've mostly used the "permission model" as an add-on, not a replacement.
But far and away, the old interruption model of advertising has prevailed. It is even prevailing on line.
More and more, online advertising techniques look depressingly like the old traditional techniques they were meant to displace.
Display ads, page takeovers, pop-ups, etc, are nothing if not interruptive. In most cases, interruptive yet not very effective.
The only place the permission model seems to be carrying the day is in social media. And outside the ideological bounds of social media zealots, the effectiveness of social media as a sales tool is highly suspect.
The belief in the permission model naively ignores a simple fact about advertising. At best it is a minor annoyance. Whether of the crass "buy this now" variety or the cunning "let's be friends" variety, very few people are foolish enough to volunteer for advertising.
Addendum: Of course, there is one form of online advertising that people do volunteer for in great numbers - search. However, in my mind I always separate search from all other forms of advertising because the purpose of all other advertising is to create demand. The purpose of search is to fulfill demand. In other words, people generally use search once they have already decided to buy. This is what makes search so different, and so effective. I also think search falls outside the boundaries of "permission marketing" as people opt into it on an ad hoc basis.