Yes and no, although you're descriptions are handy, they're not comprehensive.
The differences are not just what is in the names.
I had been asked for the reasons behind the color scheme. I hadn't seen this thread, but wanted to share my response to the question.
Actually what is the purpose of "color" market?
The Blue Market, I'm assuming, comes from the term Wall Street uses to refer to its premium companies ... Blue Chip stocks. The term Blue Chip comes from poker play, where chips are different colors for different denominations. In a typical Red, White and Blue set of chips the white might be $1, red being $5 and blue chips at $10. So it simply refers to "top shelf" stocks.
I'm making assumptions as to how GLBSE came up with the names, but they make sense.
So the next level, White market is basically "commoner" companies. i.e., more risky than blue chips but you probably are safe, the owner has provided identity to GLBSE, is valued by the varket.
The lower tier is Pink, again a Wall Street reference. Pink sheet stocks are the bottom tier. Penny stocks, including new companies that have no track record and aren't valued enough to make it onto the higher levels, as well as previously listed companies that no longer are reporting their results in a timely manner. Pink sheet stocks are often times scams, and others are high risk but end up doing quite wall too.
Black market is probably for stuff like stocks issued by anonymous (unverified) parties, possible ponzi stocks, ones that possibly operate illegally (e.g. if someone were to issue a stock to buy and sell pirated music, for instance, it might appear under black market.)