Well.... I differ, I guess. Sorta.

I decided to look up the term. Most definitions stick to something along the lines of 'an environment conducive to rapid growth and development'. One site (dictionary.reference.com) gave "overprotected, artificial, or unnaturally delicate."
If hothousing means I am creating an environment conducive to rapid growth and development, then maybe many of us *are* hothousing. I mean that in a good way.
Granted, most people are thinking of negative connotations. Unhealthy focus on certain skills to the exclusion of the best interests of the whole child. I can give my tomatoes lots of sunshine and warmth, but if I don't give them the right amount of water, no amount of hothousing is going to help them grow to be good healthy tomatoes. Perhaps some hothouse orchids require a more delicate environment, but if they are given those wonderful conditions, they will thrive into beautiful flowers. Put 'em outside in the "natural" outdoors, and, well, you just might not get nice healthy orchids - or tomatoes, if you live in a colder climate.
So, are we 'hot-housing' our children by providing the extra enrichment? IMO, we are. I am also of the opinion that for many of our children the alternative would not be healthy.
Sadly, people associate the term 'hot housing' with imposed, parent-led learning, imposed on a child in the hopes of creating something different from what the child's natural tendencies would produce. By this definition - no, you are not hothousing your child.