Disqus blog comment system adds trackbacks: Will it be enough?
But Disqus has faced a few challenges. When the service first launched, comments were not indexed by search engines. Or rather they were, but the search engine would find them on the Disqus web site, not yours. So while Disqus was adding value to your readers, you it could actually be taking some value away from your site in terms of search engine traffic. That issue was fixed in August and Disqus comments are now properly indexed by search engines.
Second, Disqus couldn't handle trackbacks properly at launch. Eventually the the developers did roll out a trackback feature. But in order for trackbacks to show up on your site, anyone linking to a post had to use a special Disqus URL, not the URL of your post. Last night, Disqus rolled out a fix for WordPress, allowing Disqus to display all the trackbacks or pingbacks to your blog.
With this latest update, I can't think of many down sides to using Disqus at this point. At least for WordPress users. But there's the rub: WordPress 2.7 will likely have many of these same features built into the platform. No third party plugin necessary. Last month Automattic, the company that develops WordPress purchased Intense Debate, a company that competes with Disqus. And if you can give readers threaded comments, commentor rankings, the ability to register once and post on many blogs without installing a third party plugin like Disqus, why would you? It'll be interesting to see how Disqus works to differentiate itself from Intense Debate once WordPress 2.7 is released.