Andy Jedynak GM Weatherbug just emailed in that Weatherbug does serve pop-unders to installed users which appear when you close the Weatherbug window. However, they limit this in three ways to keep users' trust:

1. "Severely" limit pop-unders to 1-2 per day per user, no matter how often that user opens their Bug.

2. Never ever serve contextual ads based on clicks or other surfing activity data the user displays. The only data they base ad serving on is the data the user voluntarily provides them in the registration form and other user surveys where it's clear answering questions will affect your Bug. No surfing privacy is invaded.

3. Ads stop the minute a user decides to uninstall the Bug.

Jedynak added, "As for what IT guys told you, I think they pronounced us guilty by association. Since we're a downloadable application, occasionally people will assume we do the same questionable things that other downloadable apps do, then rumors fly. It's unfortunate..."