Domain monetisers employ many tricks to draw traffic to their websites. One of them is using typographical errors, which can be due to people either typing in the wrong address (bad typing) or simply not being sure of the spelling.
A quick look at some of the bigger brand names reveals at least one prominent typo squat in the .eu namespace:
gooogle.eu – note the three o’s instead of the normal one.
The same typo has been registered (by other parties) in other namespaces, while the attempt to do so in the IE namespace failed with the registration being pulled by the registry within a couple of days.
The problem with typos is that by their very nature they are accidental ie. predicting every possible permutation of a domain name (and its linked brand or product name) is not an easy task. However if you choose easy to spell, memorable domain names it can be easier to avoid falling prey to this kind of issue.