Using a formal reading program like hooked on phonics to encourage early reading = hothousing.
For me, it depends on what you mean by "using a formal reading program." If the program dictates some kind of schedule, and the parent of a toddler tries to stick to it then I think you have a case. If a parent buys such a program, shows their child what it's about, and then the child chooses to work on activities from that program, then I don't see that as hothousing... at least not on the part of the parent.
Also, I don't think there's a definitive answer as to whether or not prompting toddlers to challenge themselves intellectually raises IQ. From my understanding of the brain, I think there's a good case that it is in fact beneficial, though in a limited way (probably not going to bring a child who would otherwise have an IQ of 115 up to 160, but might get them up to 120 or 125).
