What about words such as “flickr” and “digg” used as names by popular Internet websites?
We are all in for a lot of extra unnecessary work if the current naming trend continues on the Internet without any thought about how these names impact spell checking. This service doesn’t add these words to its core dictionaries because they are misspellings of valid commonly used words. If you decide to add these words to your custom dictionary then real misspellings of these words will go undetected. If you don’t add them then you may end up with a lot of misspelling noise in addition to your other misspelled words. Even context-based spell checking will have difficulty dealing with this problem because a name such as “flickr” can be used with a wide variety of surrounding words.