What is the big deal about Å, Ä and Ö?

Many Finnish people and internet searches will make a difference between a and å&ä and respectively between o and ö. Why? Because they are different letters.

Finnish is written phonetically. And we have more vowels than the English alphabet allows for.

Strictly speaking you don't need Å for Finnish. In Finnish it is called "Swedish-O", as it is pronounced usually the same as O and it is "swedish" because in Finnish text the place you see it in is names with Swedish origins.

But with Ä and Ö, Å is part of the Finnish alphabet. They are the 3 last letters, which might be useful to know when looking at indexes and registers.

Finnish alphabet with pronounciation from Wikibooks.