In its raw form this chemical dissolved a fraction of a second before it is exposed to water. But the indissolubility of the compound wouldn't be all that useful on the scale that Amazon operates, and that's why I suspect they've devleoped a new electrical based interaction. I have a copy of the seminal paper The Endochronic Properties of Resublimated Thiotimoline in front of me right now and there's no mention of electrical behavior. It seems that Amazon is probably keeping this a trade secret.
That is an impressive service, wouldn't it? It would literally be the fastest delivery service ever.
Not even Google could match it with their Google tISP service, which they beta tested in April of 2007. The Toilet ISP promised gigabit download speeds as well as near immediate parcel delivery, but the limited beta was cancelled due to problems cause by water pressure.
Update: If you're reading this via the email or RSS feed I strongly urge you to visit the blog and read the comments. they're funny.