I’ve just did a test on one of my test environments and it seems that the keyword “chinese martial arts” is linked. The spaces are not a problem here, maybe there is something else that interfere with the linking.
Maybe there are already enough links linked on that page ?
I see.
Yes, it is probably to do with the control for how many links can be made on a single page.
Since I have very long articles with many keywords, I need to be able to link more and have more options than your plugin currently offers.
I suggest you take a look at:
http://codecanyon.net/item/wp-keywords-to-link/6048953
See how he does it. It is a much more flexible system.
Also, he claims that his plugin supports Japanese and can deal with punctuation quite flexibly. Check it out and you might get some ideas to copy.
I also noticed that the varying post length causes problems with affiliate link limit. I have in plan to make it dynamic, based on post length.
In the latest updates I have adjusted the way the Link Frequency works. For long articles there will be more links displayed.