Donoussa is a genuine island without any major tourism. It get a little busier during high season, but most holidaymakers are Greeks from the mainland.
Donoussa has quite a harsh nature, but if you decide to go for a walk you'll meet cattle, goats and sheep here and there. Since the islanders can not survive on just tourism, most of them are involved with agriculture and fishing. The locals are friendly, but it is sometimes hard to communicate with them since they don't have much experience in speaking English.
According to some versions, Ariadne fled to this island after Theseus had left her sleeping on Naxos. This is just about the only mythology connected with Donoussa. We do not know much about the ancient history of this island, except that it was probably inhabited as early as in the 10century BC, and that it was a place where the Romans sent their exiles after they conquered the Cyclades in the 2nd century BC.
Just like the other islands, it belonged to Venetian rulers from the 13th to the 16th century, when the Turks took over. Being such a tiny island, it was not very interesting for the invaders, so pirates took the opportunity and established a foothold here. During World War II, a British warship was sunk here, and you can still discern it from the beach Kedros.
This is an island where you just relax, or perhaps take a walk through the nature. The steep coastline, the hills and the blue water are sights enough. The shipwreck at Kedros is not exactly a sight, but it is the closest thing to one on this calm little island.
Donoussa is a place for sunbathing, perhaps snorkeling a little and taking walks. That's about it! Bring something to read or why not paint! Find your own little beach and enjoy. There are many nice beaches for such a small island, and even the harbour, Stavros, has a good enough beach.
The only entertainment resembling nightlife is sitting in one of the little taverns in Stavros until late at night. This is the exception that confirms the rule: whereas most Greek islands have some kind of bars, on Donoussa there is nothing. Here you get Greek traditional food, the taverns are very few and almost all situated in Stavros.
The closest islands with airports are Naxos and Paros. It is also connected to the mainland (Piraeus Athens) through a boat line.