What is the text classification's high limit of classes number?

[guotong1988]

We can use CNN to classify more than 10 thousands of images of the ImageNet.
I find that CNN could only classify 10-20 text classes as this paper write.
So what is the high limit of short text classification's classes' number?

[ceefour]

That's interesting. Since CNN can be used to classify images into thousands of labels, I would also expect it able to classify thousands of labels when used for text classification...