Do you always buy into those hosting companies that claim to have unlimited hosting plans? What this means is that you get unlimited data transfer, disk storage and addon domain name capacity. I have come across articles that claim that nothing is ever unlimited. How true is this?
In Shared Hosting, Mostly all Hosting Provider gives you Unlimited Hosting Plan with lots of T&C which we rarely read.
Typically, In shared hosting, they accommodate lots of (thousands) websites on the same server. All the resources of the server like RAM, Bandwidth, etc is shared between all the websites. So, according to most of the shared hosting T&C, You are limited to use some specific no. of maximum resources in pick time.
They also have the restriction to fire nos. of SQL queries per Second. (Differs according to the provider.)
And common condition with all the providers is this account must be used by single person/company for all of their sites. But generally, they don't bother you with this condition as far as you are out of the radar.
In conclusion, This Unlimited Hosting is really a good option if you have lots of static websites!!
But if you are planning to take some online test/quiz where more than 20-30 people will give the exam at the same time, then you will stuck!