Last month Y Combinator startup BackType introduced a new feature called BackType Connect, allowing users to enter the URL of any blog post to see related comments on other blogs, Twitter, FriendFeed, and a number of other services. The service is quite useful but hasn’t been particularly convenient until now, as users would have to visit the BackType website in order to see the releated content.

Today BackType has launched a new WordPress plugin that allows bloggers to integrate BackType Connect functionality into all of their posts. This means that every relevant comment from FriendFeed, Reddit, Digg, Twitter, and even comments from other blogs that link to the original post can be automatically imported, allowing readers to follow the conversation on your blog no matter where it is taking place on the web.

It’s a very powerful plugin (you can see an example with it enabled on The Next Web’s coverage), and will certainly appeal to many bloggers, especially those who typically only see a handful of comments per post.

But BackType Connect has some weaknesses that will likely keep larger blogs from using it for now. For one, some of the sources (especially Twitter) can be very spammy. Blog admins can pick and choose which services they’d like to include, but it looks like the filters for services that are enabled need some work (Update: Founder Christopher Golda notes in the comments that you can also use WordPress comment filters to keep spam out). There’s also apparently no way to preserve the original comment threads when importing them, which can make some comments appear totally out of context.

I also suspect that some bloggers will object to having comments from their blog imported elsewhere. It’s one thing to present these on BackType’s website, which is essentially a search engine. It’s another thing entirely to take those comments and place them on another blog – and there’s currently no way to prevent BackType from taking your comments, save from not linking to a blog with BackType installed.

Disqus, another leading comment startup, recently launched a similar product.