My DS6 started on numbers around 18 months, I think, and then letters, and was reading road signs and grocery store labels by the time he was 2. At 2 1/2, we moved across the country, and all there was to do in a U-Haul all day was read signs and his books and PowerTouch books, and he did that all the way. When we turned in the U-Haul, the lady was shocked that he read the brochure to her! It was a few weeks after that when I realized that he had a photographic memory and said "oh, that's how he does that!" He had asked about everything on the grocery list when I was writing it, and I told him the words, and about two weeks later he asked for crackers (his favorite meal, chickennuggetsketchuptomatoranchdressingandcrackersplease, all one word) and I went to get them out of the cabinet. He was watching, and he looked up and said "Ritz" and I said "yes, Ritz crackers" and he kept going, "light bulbs, toilet paper, toothpaste..." and I realized that he was reciting the grocery list from two weeks earlier! I went to tell my mom, and he tagged along, and when I left off at toothpaste, he filled in the next few items for her. We went to tell my brother, and when we got to the end of that, he filled in the next few items as well! That's when the light bulb went on in my head and I realized that every time I told him a word, it was stored in that photographic memory. He doesn't really show it that way anymore, and I'm afraid he may have lost the photographic quality, but he still remembers everything like a steel trap--as long as he reads it.
Anyway, by age 3, he could read literally anything--sounded out words he didn't know and everything. I never taught him any of it, just told him numbers and letters and words when he asked, and he figured out phonics on his own. His "word attack" score on the WJIII test last year was >21.9 years, which is as far as it goes, I believe. Comprehension runs well behind that, of course, because he has no life experience--but I told them, he could have gotten that same score two years earlier without ANY comprehension. He's always learned things before he knew what they meant--he knew how to count as high as you could listen to when he was 2, but he didn't know what numbers really were. Comprehension comes. And I'm probably off the subject again, *sigh* what was the question? LOL!