Usually they are 3rd party items and easy to spot. But sometimes they are hidden and appearing as 1st party:
Adblock Plus Fan wrote:You do raise a good point here I guess. If they were smart, they shouldn't have made it obvious with /ivw/ in the url, and then I wouldn't have found out so easily.A wrote:But you must admit noone visitig the site
for harmful. There isn't a visible effect and the URL looks unsuspicious. Noone would even expect this is an spy image from the domain ivwbox.de, because it looks like gmx.net domain.
From this thread: http://adblockplus.org/forum/viewtopic.php?t=2766
So, something like this:
Would make life easier for the filter list maintainers. In this case we have a new column in the blockable items list which points out the item's size whenever they are below a certain threshold.
Perhaps this threshold could be configurable in about:config? Sometimes they are not always 1x1 pixels, so it could be useful to adjust the threshold to 4x4? or maybe 5x5?
Or if this is not worth the difficulty to implement, then instead of naming it Web bug, the column could be named dimension instead, and then provide the pixel size for every item when applicable. I believe this would still be a useful tool to detect them.
Personally I think an extra Web bug/dimension column could help confuse the average user, so this should be a column which is not shown in the blockable items list by default. Advanced users and list maintainers can enable it if they find it useful and the average user won't be bothered.