-네(요) is exclamatory. 이거 좋아요 You're simply saying this is good. It sounds like you're slightly insisting on it only as compared to "이거 좋네요". 이거 좋네요 You're saying this is good to someone, implying that you're expecting them to say what they think about it. If you want them to feel free to say their opinion, this is better than '이거 좋아요'. Also you can say it when you want to sound more friendly or continue the conversation. You'll notice some people say something like "좋으네요" or "추우네요". Well, I see it as a softer one although some other people will regard it as wrong. But I'm not a prescriptivist in informal situations. ________________________________ Well, it's implied that the speaker wants you to say whatever you think about it in the three examples Richardus has given...

Basically, yes. The second has the particle 네 at the end. This particle is used to express surprise: 3. Sentence ending V. + 네요 This informal sentence ending indicates that the speaker is making a remark. The speaker is not trying to inform the listener about something or get a response from him/her. * 한국에 온지 한 달이 되네요. => It's been a month since I came to Korea. * 아기가 아침부터 이렇게 우네요. => The baby has been crying since morning. * 한국에 가면 재미있겠네요? => Wouldn't it be fun if you went to Korea? Source: http://www.language.berkeley.edu/Korean/10/lesson01/01_grammar_only.htm (see number 3)