Glides

Obviously, the start of a note is used for rhythmic purposes. Instrumentally, as far as I know, only the start is relevant.

In singing, the end of the word is also relevant for rhythmic purposes. To be more precise, if a word ends in a vowel, that ending might be relevant rhythmically. But the concern here is for words ending in consonants. (And probably the "stronger" consonants, like /t/ and /p/, have a stronger effect than the weaker consonants, such as /m/. But I think all consonants are relevant.)

Hearing the Rhythmic Effect

Good luck. It is almost impossible to hear. First, I have no idea how often it is relevant, which is to say, how often the ends of notes should be used for rhythm. Perhaps it's all of the time. Perhaps it is irrelevant whenever there is a slur from one note to the next or a semi-subliminal drop.

So, I suspect that when this is done right, the song sounds better and you won't know why. When it is needed and done wrong, the song sounds worse and you won't know why. If you try to analyze it, you will have trouble telling if the note is on a beat or not. Note also that the end of the note could be used to mark the half-beat or quarter-beat.

Achieving the Effect

Reportedly, Elvis Presley jiggled his fingers (or whole body) when he was recording in the studio. This actually makes sense, rhytmically. Your body tends to have a just one rhythm, and if one part of your body is moving to a rhythm, the rest of your body will tend to follow that rhythm. That's why musicians sometimes tap their toes to stay on the beat. In this case, if you moved your fingers four to the beat, your consonants would probably fall on one of those quarter-beats without you necessarily knowing it.

I don't find this useful. I am just saying.

Examples

I first noticed this for the singing of Elvis Presley. So I think of him as a good example. Listen to You Ain't a Nothin' but a Houndog. It rocks. It doesn't rock as much as a modern song might, but for the time, it was a rocking song. However, the musical accompanyment doesn't rock; the drums don't rock; and the melody itself doesn't rock. The only rock seems to be in how Presley sings it, and I think the whole of the effect is achieved by including the ending consonants in the rhythm.

I have also noticed Karen Carpenter being good at this rhytmic effect.

In contrast, on her first CD, Leona Lewis sings the song Ever I Saw Your Face. It is a great CD and I love her singing, but.... The /c/ sound in "face" seems out of place. It is like she tried to fade out on that note, which would be fine, but then was stuck with the ending sound and had no place to put it.