AtD really is going from strength to strength. The removal of the requirement that you register for an API key makes it even easier to integrate into your site but, for me, the bigger news is that AtD now proofreads 5 languages, with another 4 or 5 in the pipeline.

The current languages are:

English
Spanish
Portuguese
German
French

... which, in terms of native speakers, covers about 1000,000,000 people!

According to a comment on the Atd blog, Raphael is aiming, in this first round, to cover about 90% of WordPress.com users, he figures that the next 4 or 5 will bring him up to that.

This is exciting because the availability of easy proofreading will give far more people the confidence to express their thoughts online. WordPress and online discussion generally are going to be the winners as more people, in more languages, adopt tools such as AtD.

If you want to increase the number of comments your site gets, be sure to integrate AtD and write a post to introduce your users to the idea. If we all work together to make users aware of the option, we will all reap the benefits of more and better comments.