plus: When to Pronounce the S

I was looking up the e-mail closing expression À+ when I noticed a discussant's mention of the fact that, when saying à plus, one should pronounce the ending s. Really?

Yes, really:

A note on pronunciation: plus/le plus used in comparison (meaning more/the most) is pronounced [ply] before a consonant and [plyz] before a vowel. It is pronounced [plys] when at the end of a clause. In the plus de and plus que structures both [ply] and [plys] are generally used. plus used in ne plus (meaning no longer/not any more) is always pronounced [ply] except before a vowel, in which case it is pronounced [plyz]: il n'habite plus ici [plyzisi] [WordReference.com: French-English Dictionary entry for plus].

So if you are saying, "À plus!" to a friend, that plus is indeed at the end of your clause, and you do indeed say it.

One also pronounces the s on plus when using the word as a noun for the addition sign or for an advantage:

1. Le professeur a oublié le signe plus dans la formule; ainsi, il a prouvé, que la terre est plat.
   
2. Un jour de neige? C'est un plus pour les élèves qui n'ont pas fini les devoirs!