In part 1 of Why You Don’t Want Flash, we explained why Flash-only websites are bad. But using any Flash at all on your website is becoming a worse idea on a daily basis. The main reason is the growth in mobile and tablet browsing, specifically the use of iPads and iPhones which do not support Flash.

Mobile

According to Nielsen, 28% of the U.S. cellphone market was smartphones in November 2010, and market share was growing by 2-3% each quarter partly because over 40% of new cellphone buyers were choosing smartphones. So by now, smartphone are probably nearing 40% of the market.

With 303 million cell phones in the U.S. (according to CTIA – The Wireless Association) that’s about 121 million smartphones. iPhones now make up 27% of those smartphones, so your flash banner ad, photo gallery, game or other visual website feature won’t show up for at least 33 million cellphone web surfers. And although wireless speeds are picking up, most users would agree that Flash is not ideal on other mobile formats either.

The number of mobile users Flash doesn’t work or work well for will only grow. Nielsen found that 51% of those who own an iPad, but not an iPhone, plan to buy an iPhone the next time around. 25% of those that don’t own either one would like an iPhone instead of their current phone.

Tablets

By the end of March, Apple had sold 19.5 million iPads (in about 1 year), none of which support Flash. And here’s what is even more important—Nielsen reports that 35% of tablet owners used their desktop machine less often or not at all since buying their tablet. Fewer and fewer eyeballs for your Flash banner ad.

Alternatives

Here’s the good news. There are alternatives out there to Flash. YouTube already uses the HTML5 video tag to provide mobile and iPad users with video instead of the usual Flash player. As HTML evolves it will only get better at displaying video. There are also a lot of options, from animated gifs to Java scripting to make your website or banner ad more than just a static page—and they’ll be viewable in the future by the millions more that will do their surfing on iPhones, iPads and other mobile devices.