According to MacStories, there are now 100,000 iPad apps available.

While the number hasn’t been verified by Apple, it’s a significant milestone for the tablet, which launched just a year and a half ago.

More and more, the quality and quantity of available apps are seen as a critical factor in the success of mobile platforms.

An example of this surfaced as recently as last night, as reviews of the webOS-powered HP TouchPad began to surface.

Joshua Topolsky at This is my Next:

[quote]The other issue HP has right now is the lack of developer support. Although the company says 300 tablet apps will be available at launch (more than Honeycomb could boast), the level of really high quality applications is still few and far between.[/quote]

Tim Stevens at Engadget:

[quote]The selection in the App Catalog is quite good, but the subset of apps actually optimized to take advantage of the full display here is quite slim. HP pledges to have 300 TouchPad-optimized apps available in the Catalog in time for the launch, and a further 6,200 from phones. Those apps will be mostly unable to make use of the resolution, running in a small picture of a phone, which is a little quaint but also disappointing, especially since you can’t even rotate that faux phone from landscape to portrait. [/quote]

Macworld’s Jason Snell:

[quote]So what I’m saying is, I’m glad that HP finally shipped the TouchPad. If it can get developers engaged in its platform and iron out all the bugs while also growing webOS as a smartphone operating system, it might really have something here. But that’s a story about the future, and about potential.[/quote]

Uncle Walt:

[quote]When HP bought webOS a year ago this week as part of its purchase of the system’s inventor, Palm, one hope was that the giant company’s clout would attract lots of apps to the platform. But the TouchPad will launch with just 300 tablet-optimized apps and only 6,200 webOS apps overall, most written for phones and only 70% of which can run on the tablet, in a small, phone-size window that can’t be expanded. That compares with 425,000 total apps for the iPad and 200,000 for Android tablets, nearly all of which can run on tablets even if they aren’t optimized for the tablet.[/quote]

Now, it is easy to pull selected sections out of other people’s stories to build an argument. That aside, apps have become a force that can make or break mobile platforms. Apps create excitement and platform lock-in, which is good for companies like Apple, but bad for others trying to compete with the iPad.