Most technical issues with web hosts are due to the fact that it's price led, as in cheapest host wins, you can keep costs down by placing a lot of websites onto a single host (shared hosting) which causes problems when a single website is consuming all the CPU & memory resources (either through intensive resources required for things like java based chat boxes or because they are getting spammed)
You can also keep the costs down by providing "dedicated" hosting via virtual machines - so this time rather than loading a computer up with lots of websites all using the same resources, you are loading up a lot of virtual computers onto a single physical machine, with again the same issue that they are all competing for the same resources,
This isn't a problem until you over subscribe the resources - then you have issues with multiple virtual machines attempting to access the physical drives at the same time (lots of read/write = increased failure rate for hard-drives) - you also have an issue as mysql (the database software) may need the service to be paused to run the backups, if you don't then you risk corruption...
Again - other ways of keeping costs down are on technical bods - daily tasks such as testing backup integrity takes time to do and increases cost....in a market driven by low cost high volume - you could automate this process but again this increases engineering costs.....
Trouble with web based services is unless they are completely open you never know what they are using to deliver your service - you also don't know anything about their processes & procedures and also don't have any comeback due to failure (most SLA's aren't worth anything when you look at service credits for downtime)
In short....don't get the cheapest hosting package you find and don't rely on your host to backup your data - most will give you FTP access and if it's dedicated hosting you can schedule your own backup and then FTP it off site somewhere for safe keeping,
Didn't mean to post all that - can you tell I work for an ISP and get asked why we aren't the cheapest in the market place quite often? one of my bug bears - don't get me started on broadband
And after all the above - you can't mitigate against all scenarios, so even with the best will in the world & with a solution designed to remove all risk associated with unexpected outage there will always be something that can bite you in the arse - the hosting for TLB might have been fantastic but when you add issues on top of each other (hard drive failure + corrupt backups) then it comes to a grinding halt!
Best of luck getting it back up and running again!