How do I say whether I like an idea?

You express your opinion about an idea by voting on it. When you vote, you're assigning a predetermined number of points to the idea. For example, a vote in favor of the idea could give it 5 points, while a vote down could give it -5 points -- effectively removing 5 points.

To vote on an idea:

Go to the idea in the community.
Under the idea's title, click the up arrow to vote in favor of it, or click the down arrow to vote against it.