A dictionary for stutterers maybe? (Couldn't resist!)
I have a dot-com that is a sticky-keyboard domain like your ddictionary.net. It gets a fair amount of type-ins but it doesn't do well in producing revenue. I'd say that the more traffic you get for such a name, the more it's worth. Otherwise, it's worth whatever someone is willing to pay for it, but probably not a high-value domain name.
PS. Dictionairey.Com is available... You might get some misspelled traffic from that name.