Some people whose posts may otherwise have been deleted by censors in China have taken to writing backwards in an effort to defeat keyword-searching authorities.
"Bloggers on forums such as Tianya.cn have taken to posting in formats that China's Internet censors, often employees of commercial Internet service providers, have a hard time automatically detecting. One recent strategy involves online software that flips sentences to read right to left instead of left to right, and vertically instead of horizontally," write Juliet Ye and Geoffrey Fowler in The Wall Street Journal.
This is a particularly clever solution in Chinese, which, because of its ideographic writing system, is probably easier to read in odd inversions than most alphabetic languages. One way to imagine this is to remember the English phrase "bass ackwards," a well-understood inversion. Because Chinese splits words into meaning-based units rendered in characters, reading reverse text is more akin to "bass ackwards" than to "sdrawkcab ssa." At least, I think so. We'd have to ask serious linguists to confirm my hunch.
Another circumvention method that has been in action for many years is to write the text and take a screenshot of it. Censors aren't very good at parsing text in a JPEG file.
I don't know whether this is the first time this tactic has been used, but it's one indication of the determination of some people in China to exchange information despite state efforts to control online communications.