As is his wont at Apple press events, Steve Jobs shared some of the numbers related to products connected with the iPhone OS 4 sneak preview, with iPad sales front and center.

After Apple announced that 300,000 iPads had been sold on the first day (meaning, via pre-order and on 3 April 2010), many people wondered if the iPad would maintain its sales velocity. The answer would seem to be yes, with Jobs stating that as of 8 April 2010 Apple had sold 450,000 iPads, meaning that another 150,000 left shelves in the subsequent four days (one of which was Easter Sunday, when few Apple Stores were open).

Given that the best estimates we've seen put Amazon's Kindle at somewhere over 1 million units sold since its 2007 launch, for Apple to reach nearly half that number in less than a week indicates just how much more significant the iPad is than the Kindle, a comparison that was much debated before the iPad was formally announced and that has continued even after the iPad shipped.

Similarly, though Amazon won't disclose how many Kindle books it has sold, Apple is less shy, announcing that 250,000 books were downloaded from the iBookstore on the first day. That number rose to 600,000 by the iPhone OS 4 announcement, though Jobs didn't distinguish between free and paid title downloads. Apple makes available tens of thousands of free books from Project Gutenberg, and promotes a list of top free downloads alongside top paid ones.

Apps have been even more popular, with 1 million iPad-savvy apps downloaded on the first day; that number grew to 3.5 million four days later. Again, Jobs didn't differentiate between free and paid apps, though he did note that there are now 185,000 apps in the App Store, of which 3,500 are iPad-savvy (running either solely on the iPad or available as universal apps that can run tailored for either the iPad or iPhone).

If all those numbers sound positive, the ones that most shocked us were the iPhone and iPod touch sales figures. Currently, Apple says it has sold 50 million units of the iPhone and another 35 million of the iPod touch, worldwide. Add in the iPad and Apple is closing in on 86 million iPhone OS devices out there.

That may not put the iPhone ahead of RIM's BlackBerry yet, but Jobs did share a slide claiming that the iPhone accounts for 64 percent of U.S. mobile Web browser usage, with phones based on Google's Android at 19 percent, BlackBerry at 9 percent, and the rest filling in the final 8 percent.

At TidBITS, in the week beginning 3 April 2010, about 5 percent of visitors used an iPad to view our pages, with about 7 percent using an iPhone and 1 percent an iPod touch. That's a significant spike for a just-released device - glad you thought to come to TidBITS! We're not alone - Alaska Airlines tweeted that the iPad became the second most used device to access the company's Web site in less than a week.