I am not usually particularly passionate about laundry detergent, but I read about Dizolve about a year ago and decided to try it out. (FYI: I am not on the Dizolve payroll in any way!) It is truly an innovation in the world of detergent! Dizolve consists of small, harmonica-sized, pliable strips that are not only biodegradable, but also packaged in a small, recyclable cardboard container. And it works (including with high-efficiency washers)!
This is a particularly exciting product for apartment dwellers, especially those who go to a laundromat (so much less to schlep!), but it is really great for anyone who cares about the environment. And as a bonus, company, which is Canadian, donates a portion of its proceeds to the Sierra Club and other nonprofits! There is really nothing not to like here except for the fact that so far I have only been able to order it online. If you order 2 packs, there is free shipping, so it comes out to 20 cents per load (comparable to Tide). I have been using it for several months now (and even got my mom some), and Dizolve has worked quite well for all my laundry, including socks!