Oh neato, we're talking about ethnicity and such. I kinda know a few things about that given my own background.
Taiwanese ppl back in the day, say 500 yrs ago could be called indigenous to the island, although they probably migrated over from China. Same with Japan, though that happened even earlier. You can tell by popular clothing of the time, architecture, and stuff like that when the migrations happened.
Anyhow, in more recent history, Japan occupied Taiwan for quite a while, so the gene pool got a good shuffling during this period. The indigenous language, Taiwanese remained, and it still has strong ties to dialects in Southern China nearest to the island, particularly Fujian province. That's obviously the point of migration back in the day.
There are tons of dialects in China. Some of them are more like accents, but they're called dialects anyway. As a Mandarin speaker, I can understand a lot of dialects, but some, like Taiwanese and Cantonese have evolved so much that I can't understand it. Some words are still the same, but most aren't.
The written language in any dialect is more or less the same. The reason for this is because China is so huge, and people tend to live in isolated groups. To communicate between groups, they used mail - written letters. The speech of each isolated group evolved independently over time, but the letters kept the writing consistent. Can't change the writing because you wouldn't be around to explain the change to the other side.
When the commies took over China, a lot of people who were loyal to the original gov't fled to Taiwan to avoid oppression. They promptly took over the gov't there, which really really pissed off the local people. Ever since, there have been tensions between Taiwanese and "mainlanders." Lots of descrimination and racism. Even though we all look alike to the westerners (heheh), I can usually tell if someone is Taiwanese or not. The gene pool shuffle I mentioned with Japan really helps. It goes both ways. People can tell your background by your genes, so they had basis to discriminate. Over time, the local Taiwanese reclaimed the government, and these days they are trying to emphasize that they had their own roots, and that their political philosphies are different from the mainland, so they should be recognized as an independent country.
Meanwhile, China was pretty much demoralized by the West when they demanded open trade... the opium wars, and the occupation of Hong Kong, etc., so they are especially sensitive to losing their territory. Which is why they cling to Taiwan as part of China. Same with Tibet. Don't want to get too much into the politics, since this really isn't the forum for it.
In modern Taiwan, their pop culture is most influenced by Japan, more so than neighboring Asian countries. Korea used to be the same, but they are starting to carve out their own identity as a big player. Well, at least the south is. The North is just.... sad. Many of S Korea's industries are now surpassing the quality of the Japanese. Taiwan is also making huge strides in technological advances. As a kid, I remember hearing my parents always cursing at the shittiness of things "Made in Taiwan." And they were right. Now they can't say that anymore. HTC is a great example. Hyundai and Samsung are good examples from Korea.
And that's why the home icon has been simplified (see? I was on topic the whole time).