I've had a quick look at your site because I'm currently using DO and Vultr with a PeerVPN[0] setup to connect the individual hosts - which brings me to my question:

Is it just a static website or do these instances communicate with each other? If you do, I'd like to ask if you use a VPN to connect them (and which one)?

I'm relatively happy with PeerVPN (with one or two rather minor annoyances that most likely can be solved if I actually spent time on them) but am always curious about alternatives.

[0]: https://github.com/peervpn/peervpn

The site is mostly static, expect the server-side Python code to handle the submission of blog comments. I use no VPN but have automated rsync runs, over SSH, to sync data files periodically. A description of my setup is at: http://blog.zorinaq.com/release-of-hablog-and-new-design/

> I like Vultr because they accept Bitcoin payments.

This. I've been a loyal Linode user for years but recently gone with Vultr for side projects because they accept Bitcoin and had a $5 plan long before.