The federal government gave them the largest government contract ever issued to any one company, including Microsoft, to completely overhaul the United States Patent Office using this very technology. They are also co-developer of the FDA's electronic documentation system that all drug companies and such have to use.
Right after these two things happened Microsoft "conviently" inserted the ability to interact with those agencies electronic documentation systems, which are not standard XML, into Word after entering into a collaberation partnership with i4i, getting their hands on the code and then desolving the collaberation as having no worthwhile outcome. Then turning around a short time later and releasing the code in Word.