The Interactive Advertising Bureau (IAB) has booted Adblock Plus from its yearly conference with little more than "sorry, not sorry." The company, which boasts more than 400 million downloads of its ad-blocking browser extension, was dismissed with a curt email from the IAB, according to an Adblock Plus blog post.

A screenshot posted to Adblock Plus's blog shows an email exchange between the company and the IAB, in which a representative of the IAB simply states that Adblock Plus's registration had been canceled and the fee refunded:

The decision was seemingly out of the blue, given that Adblock Plus had even been included in the participant lineup on the IAB's website.