Echo is the next generation commenting system. It's the way to share your content, and watch the live reaction. You can quickly embed Echo on WordPress, Blogger, or any website and turn your static pages into a real-time stream of diggs, tweets, comments and more.
WeBlog is a blog module for Sitecore 6.2+. It is the successor to the EviBlog module.
Features
Windows Live Writer integration (MetaWeblog API)
Page Editor support and custom WebEdit ribbon
Wordpress Import
CSS-based themes, with custom themes possible (one included)
Various blog navigation components
Comments (with author notification and optional approval workflow)
Comment CAPTCHA through MSCaptcha or reCAPTCHA
Gravatar Support
Social sharing through ShareThis or AddThis, and other Facebook and Twitter widgets
Tagging and tagcloud
RSS Feeds (Sitecore Integrated RSS)
Multi-server (staged architecture) support
Globalized labels and messaging (English, Danish, Dutch, and Japanese translations provided)
Most importantly, WeBlog has been architected to allow you to easily integrate it into your existing content and design, and to allow you to customize its templates and layout to your project requirements.