The majority of Taiwan's expat community consists of English teachers here feeding the demand to learn English from native speakers. They are a tight-knit group who support eachother through various Facebook groups.
There is also a sizeable professional group of expats working in Taiwanese companies and startups in various marketing positions. They are responsibile for putting these companies' products on the map for the global market. It's not easy to get an office job in Taiwan as an expat, but those who do learn that the local corporate culture can be frustrating and the pay isn't very high. This group also tends not to mix with the English teachers as they have different priorities.
The other main group would be the students. Taiwan is arguably the best place in the world to learn Mandarin Chinese, through one of the many university programs. There are also dozens of universities with sister schools in the West who have exchange programs. This group also tends to stick together and they party pretty hard.
Finally, there is a small group of "lifers", who start as students or teachers, and make their way up the totem pole, usually running their own succesful business and settled down with a Taiwanese spouse. They have seen it all but have found a home in Taiwan and aren't leaving anytime soon.
In general, and compared to other Asian countries, the expats in Taiwan are hard working and ambitious. Strike up a conversation with any of them at a bar and you can learn a lot about the expat experience.