Hoping to keep the dampening effects of the recession at bay, top web publishers have committed to develop three new ad units — all markedly larger, and potentially more invasive, than existing ad offerings.

AdWeek reports that members of the Online Publishers Association — including The New York Times, Wall Street Journal and ESPN — have agreed to avail the following ad units to advertisers:

• The fixed panel, a 336-by-860-pixel banner. Wider than standard skyscrapers, it follows users as they scroll down the page.
• The XXL, a 468-by-648-pixel box with an expandable video option.
• The pushdown, a 970-by-418-pixel unit that takes up over half of a page before rolling up.

The new ad units, which go live in July, shall operate outside industry specifications set by the Interactive Advertising Bureau.

"As we talk to the agency community, one of the things we hear is they need new creative ways to connect with our audiences on the page," said President Pam Horan of the OPA. "These ad units are providing a new palette for them to connect with the audience."

The OPA, which consists of over a dozen of the most-trafficked online content sites, represents 108 million monthly users.

Earlier this month, Google began exploring expandable ad units for AdSense and AdWords. In February, Yahoo announced plans to introduce video and image options into sponsored search — but only for select top-level clients.