Major outages should absolutely weigh into your decisions as to what platform to use. That being said you can mitigate the effect of instability by engineering your app to failover to other availability zones or even to another cloud platform (depending on your app) if the entire platform goes down.
Obviously there is a segnifigant cost associated with engineering this level of cross platform redundancy which is why reliability is an important factor in making your platform choices. If you can tolerate some downtime, you can be more flexible, otherwise it will costs one way or the other.
In any case you should consider having a user notification site setup on a completely different service (or two) so that when things go wrong you can redirect everyone to that site to keep your customers informed. This is especially important when you have partial outages that could create inconstancies in your database or application state if you where to continue to allow users to interact with it in a degraded state.
Our big hosted site is hosted in Europe is actually working but our blogs and a news website are both down. We offer a paid service at 600$ a year and if the main site was down it would be very bad for our reputation.
Our DNS points to Azure on all these domains and things are hosted as "Azure Web Site" - how would notifications work if Azure itself is failing? Would I need to proxy the traffic through elsewhere?
Are there any services that solve this problem for me? I really don't mind paying a few dollars every month and not worry about this.
There are any number of uptime, and ping services that you can google for. This can raise the alarm in a timely fashion when your site, or parts of your site go down, and then you decide how to handle those issues.
You may also want to google for DNS failover services, to help you automatically redirect traffic in more catastrophic failure cases. There are offerings from google[1], AWS[2], and others.
Obviously there is a segnifigant cost associated with engineering this level of cross platform redundancy which is why reliability is an important factor in making your platform choices. If you can tolerate some downtime, you can be more flexible, otherwise it will costs one way or the other.
In any case you should consider having a user notification site setup on a completely different service (or two) so that when things go wrong you can redirect everyone to that site to keep your customers informed. This is especially important when you have partial outages that could create inconstancies in your database or application state if you where to continue to allow users to interact with it in a degraded state.