今天尝试为自己开发的博客加上评论功能，查看Django的文档，发现1.6之后Django不再自带comments这个app了，下面是官方文档上的说明：

Django’s comment framework has been deprecated and is no longer supported. Most users will be better served with a custom solution, or a hosted product like Disqus.

The code formerly known as django.contrib.comments is still available in an external repository.

虽然不再自带，但是仍然可以自己安装实现。根据文档的指引打开下面这个网址

http://django-contrib-comments.readthedocs.org/en/latest/index.html 根据网站中所示的步骤一步一步进行操作：

1. Install the comments app by running pip install django-contrib-comments.

2. Install the comments framework by adding 'django_comments' to INSTALLED_APPS.

3. Run manage.py syncdb so that Django will create the comment tables.

4. Add the comment app’s URLs to your project’s urls.py:

urlpatterns = patterns('',         ...         (r'^comments/', include('django_comments.urls')),         ...     )

5. Use the comment template tags below to embed comments in your templates.

这里需要注意在settings.py的INSTALLED_APPS中，除了增加django_comments外，还需要增加django.contrib.sites，就像这样：

INSTALLED_APPS = (

    'django.contrib.admin',

    'django.contrib.auth',

    'django.contrib.contenttypes',

    'django.contrib.sessions',

    'django.contrib.messages',

    'django.contrib.staticfiles',

    'blog',

    'text_markup',

    'django.contrib.sites',

    'django_comments',

)

然后我试着在模板中调用comments：
{% load comments %}
{% get_comment_count for post as comment_count %}
保存后打开网页，会抛出错误提示：AttributeError: 'Settings' object has no attribute 'SITE_ID'
上网搜索了一下，查得这是因为在settings.py中没有指定SITE_ID导致，我猜测是因为刚刚添加的django.contrib.sites需要指定SITE_ID。在settings.py中任意地方添加SITE_ID=1,问题解决。