Each 100 mark is usually somewhat meaningful to the individual player. I'm not aware of 1700 being some kind of universally meaningful mark though.
Improvement usually happens in spurts. You'll have to wait and see if the win streak is due to improvement or something else.
I just reached 1700, and I was wondering if this was some type of special milestone as a chess player? And also while I'm at it, I've been going on a really long winning streak recently and I was wondering if it is normal or if suddenly I just got 10 times better over night.