How Do I Use Windows Snap?
The Snap controls are a little bit hard to explain because they rely more on user intuition than 'logical' rules. Here are the essential 'commands':
To expand a window to full-size (but not full-screen), grab the window's menu bar and drag it up to the top. You should see a transparent outline of the action before it happens.
To expand a window to half-size (of the whole screen), grab the window's menu bar and drag to either the left or right edge of the screen. Again the action will happen transparently to give you a preview. If you use another window and drag to the other side of the screen, you can view two windows side-by-side.
To maintain a window's width but get maximum height, click and drag the top or bottom edge of the window and expand it until it reaches the top or bottom edge. The other edge will automatically expand as high or low as it can.
These are the primary functions of the Snap feature. Some windows and objects are also more sensitive to their position on the screen and will fall more easily into a grid than before, so you might also consider this part of the larger Aero work environment.
[Aero Snap Demo image from How-To Geek]
On the next page you'll discover how to Enable and Disable Aero Snap on Windows 7.