You've talked about acidophilus and bifidobacterium in the past. What has changed?
Yes, I've spoken about those in the past because they are the primary probiotic strains found in cultured foods, such as sauerkraut, and are indeed very valuable in aiding digestive health. I still feel that way and continue to eat and recommend cultured foods--including on my blog, in my books and in live lectures.
The distinction is that, when it comes to a probiotic supplement, I choose to focus on types/strains that are more beneficial and yet also more difficult to obtain through one's daily diet--which holds true for soil-based organisms (SBO's).
As we mentioned earlier, SBO's are largely lacking from the diet of anyone who does not eat unwashed wild food, or organic food straight from the garden--which is typically very rare. And taking a full spectrum of SBO's better reflects both what's found in nature, and also the ideal constitution of our gut microflora.
Last but not least, compared to those popular strains, SBO's are impervious to stomach acid, are assimilated more readily, and do more to keep pathogens at bay, while aiding the proliferation of many different strains of friendly bacteria.