"In the book of life, the answers aren't in the back." -Charlie Brown, Peanuts
Yes - I've just come back from Vietnam and noticed this symbol widely depicted as well - in Buddhist and Confucius temples as well as being a general motif. Curious, I asked what it meant. I was told it roughly equated to the greeting you get everywhere in Vietnam: "Have a good long life". But when I probed deeper, was told that it could mean not just a good long life in the 'here and now', but also have a 'beyond death' sense. I'm not sure if this is technically true - but it appeared to be an understanding held in folk belief. Which made me think that it was, as it were, an aspiration of what Christians call 'being born again' - a quality of life now and one with a promised eternal dimension. Unfortunately it didn't carry any information with it as to how to achieve this - unlike that attached to a personal faith in Jesus Christ as one's saviour.