MSNBC.com recently began running a rectangle ad on the site homepage that showcases the individually-branded sites of Countdown, Nightly News, Scoop, Today, NBC Sports and recently-acquired Newsvine.

The ad allows users to click arrow buttons on either side of the container to show the next site screen shot, which appears after a quick transition effect.

This is a creative way to promote sites, but also runs the risk of being tuned out since it’s in the same position as regular ads normally are.

This also marks one of the first times MSNBC has promoted Newsvine. MSNBC has been linking to conversations and topic pages on Newsvine for select stories, but this marks one of the most prominent cross promotions.

CNBC made effective use of one of its in-studio rear projection screens today to help explain the events in Georgia and their possible effects on business.

Courtesy of the Online Design Digest blog, NBC has rolled out a new look for WeatherPlus.com. The new design features a light blue background with individual content modules topped by dark blue headers.

Internal content has also been better organized and now features some nifty dynamic effects.

The site’s navigation now features drop-down menus that have dashed outlines that make them look oddly like coupons.

It will be interesting to see how this new direction for WeatherPlus.com plays into NBC Universal’s planned acquisition of the Weather Channel, which includes the hot domain Weather.com.

MSNBC was using a different location for Weather Plus updates at 30 Rock this afternoon. The network had moved away from using the Manhattan studios for weather updates on MSNBC, opting to use WeatherPlus headquarters at CNBC in Englewood Cliffs, N.J. instead.

When weather does originate from New York City, it is typically done from the balcony area, but today Jeff Raineri was reporting from the newsroom floor, with a handheld camera used. Raineri used the desktop computers to control his on-screen graphics as well.

By the way, the cable on the right side of the screen is a nice touch.

UPDATE: About thirty minutes later Raineri was back up on the balcony: