Agility will increase your ability to dodge blows and the armor skill of your choice will increase your ability to absorb damage while wearing armor that works with that skill. At the moment there is only leather armor available which requires the light armor skill. In the future you\'ll also be able to use the shield handling skill to avoid damage with a shield but this doesn\'t work yet.
The colors of the glyphs can usually tell you what way they are for, yes but sometimes the differences in colors are subtle. If you don\'t know .. try asking an experienced mage in-game.
There is one way to log out besides closing the client, that is crashing and having the client close by itself. Then again I\'ve heard there isn\'t really a difference between the two. In other words, no you always have to close the client also when you just want to switch characters.
The limits for each stat are currently determined by the available trainers, so yes there are limits. They can be different for every stat and skill though and just because a specific trainer stops teaching you the skill doesn\'t mean you\'ve reached that stat or skill\'s limit. You might just have to find a better trainer.