请求RESTful的解释

[n00b1]

For an API or web service to be RESTful, it must do the following:

1, Separate the client from the server
2, Not hold state between requests (meaning that all the information necessary to respond to a request is available in each individual request; no data, or state, is held by the server from request to request)
3, Use HTTP and HTTP methods (as explained in the next section).

如上这段是我摘抄的第2、3点我大致能够理解(也麻烦各位帮忙看看理解是否正确)
2, 一旦有从client到server的request，server都会无条件的返回相应的response，譬如，我按照twitter给出的API去拿twits，twitter立马就会给予回应，返回相应的twits不能不给
3, 就是用那些HTTP (GET, POST, PUT, DELETE)方法

唯独第一点有点不明白，客户和服务器分离？客户服务器本来就是分离的呀，难道有不分离的情况？

[binux]

“一旦有从client到server的request，server都会无条件的返回相应的response，譬如，我按照twitter给出的API去拿twits，twitter立马就会给予回应，返回相应的twits不能不给”

可以不给，但是必须告诉你，我不给你

[ninion]

推荐一篇文章，希望有帮助
http://chinese.catchen.me/2012/05/restful-rest-in-practice.html