[dangerous]

Another ripoff from adblock:

Usually when an advertisement is blocked it still shows up as empty space on the page. With this option enabled Omniweb should try to remove this empty space after blocking something.

[Floach]

Omni Group are aware that this is a wanted feature, and I imagine it's in their database. In the meantime, just having a good CSS file for blocking stuff will make the most difference, rather than relying on the "Block known ad sizes" feature, which I leave turned off. An easy way to get rid of the obtrusive OW "transparent box" for blocked ads is to Show Package Contents on OmniWeb.app, drill down to Contents -> Resources and delete the files called BlockAdBottomLeft.png, BlockAdBottomRight.png, etc. You'll still get an off-color box where the blocked ad is, but none of the annoying borders.