Hackers don't really need word processing for their day to day jobs, but Writely's a killer. Also, geeks don't read ads, but it's Google's bread and butter. I would chalk Google's success up more to great execution (or buying great execution) than anything else, whether it appears their engineers need the product or not. The main places Google has failed have been sites where the network effect is crucial; they don't do so well with community sites. If Zenter's got some of that secret sauce, then, I'm guessing they'll be fine. Otherwise, :(

I disagree with the premise that Google is only good at making product's that its own hackers use (See aston's points below).

Nevertheless, even if we assume that this is true, many of Google's employees, including tech leads, produt managers, VPs, do give slide presentations. These employees have huge influence on the products and thus its very likely that Google "Presenations" will be more like Gmail than Google Video.