For a while, I've been reading a blog called Liquid E-Learning by Michelle Gallen. While the blog covers a range of e-learning topics, Michelle pays special attention to language-learning sites such as LiveMocha, italki, palabea, voxswap, SlovoEd, and Talk Irish (her own brand-new Irish language learning site). You can get a good feel of the focus and features of the sites from her posts. She also includes her take on each site, discussing highlights as well as areas that are lacking. As she puts it in the blog's description, "what's new, what works and what's plain daft."
Liquid E-learning is great for anyone looking to find new language learning sites and get the low-down before devoting time trying them out. It's also invaluable for us as designers to get a feel of what works and what doesn't on other sites when we're building new tools for Lingro.
Speaking of new tools for Lingro, Michelle's blog is now sporting the Lingro badge. I would expect a popular blog like hers with lots of language-learning content to have a decent number of readers who don't speak English as their first language. With the badge, those readers have a quick way to open Liquid E-Learning in the web viewer. The blog also includes the Lingro contributor (scroll to the bottom of the site), which lets multilingual readers help build Lingro's open dictionaries by giving them a way to contribute missing translations.
Liquid E-learning is definitely worth a read. If you know of any other good language-learning blogs, feel free to leave a link in the comments.