String/limb grooves, what is the purpose?

[Flying Dutchman]

Ok,

Question is simple...what is the exact use of limb grooves we see on recurve limbs? I thought the purpose was to see if your string is aligned on your bow, but some friends of mine say it is meant to keep the string on its place.
I can't imagine that, because as soon as you pull your bow, the string goes out of the grooves...
What are your thoughts about this?

[Keefer]

I have always thought it was to make certain that "IF" the string starts to walk Left or Right of the groove that you would see that the string isn't centered with the limbs and the limb can be twisted back to center...    

uh-- keeping the string aligned to the limb at rest. Otherwise the torque would twist the limb.

[kat]

I always thought it was to keep the string in the middle of the limb, when the string is at rest, which is the vast majority of the time.

[Flying Dutchman]

Allright, keep um coming.. A bowyers point of view would be interesting  too....

[bowfanatik]

If is bow made well that is not necessary . But bowyer put that grooves like prevention , if after some time limbs start to twisting that will cover problem . Problem  !?!? Is not some big problem is just unpleasant to see on bow . I shoot couple bows with twisted limbs without any problem like accuracy or loudness ....

[Dale in Pa]

I've read that it helps center the limbs at the moment of release. The string falls back into the groove instead of vibrating around on the limb.