CiM is discontinuing using the term "Uniques" - as nobody really understood what it meant. They are now using the designation "Limited Run" - which opens the door to new possibilities in terms of making one-off runs of a colour for a specific need. Uniques sound like the colour was made by accident, and Limited Runs sound deliberate - so I think that it is a very smart move on their part.
The CiM colour palette currently stands at over 60 colours (woohoo - I remember when it was about 5!). They can add colours ad nauseum - but some colours are more in demand than others, and not everyone wants every colour. (I like to collect the whole set - but we know I'm crazy and obsessed.)
Limited Runs can be made to accommodate requests for a specific colour, and can be made again in the future, but will also let you know that it is outside the regular colour palette - so if you love it, buy a lot of it or request that it be added to the regular colour line-up. (Which they might well do!)
They have also discontinued some slow sellers, colours that are really close to other colours in either the CiM line up or duplicate a Effetre/Vetro colour, and/or pricier or just plain hard-to-make-consistently colours.
These are the discontinued colours:
505 French Blue
512 Halong Bay (OK - I know I will be buying up every stick of this I can find!)
652 Count von Count
703 Butter Pecan - will probably continue to be available occasionally as a Ltd Run.
ALL stringers with the exception of Hades, Tuxedo, Clear, & Peace.
So now you know. ;-)