Unlimited Web Hosting is Not Truly Unlimited
Did you know that "unlimited web hosting" as most hosting providers advertise it, is actually not unlimited?
Yes, you heard it right: Unlimited Web Hosting, in the manner most web hosting companies are advertising it, is not really as unlimited as you would think. The term unlimited is used only with shared hosting accounts to usually account for storage and bandwidth but it is never used with virtual or dedicated hosting options simply because it is not literally meant.
While the above statement is true, you may never realize that your hosting is not unlimited if you have one single website that is hosted on an "unlimited" shared hosting account and your site gets very minimal monthly traffic (a couple of hundreds of visitors a month). You may also not notice it if you have a moderately large website that gets a medium amount of traffic, up to a few thousands of visitors a day. The reason for that is that the resources and bandwidth your website(s) will be using in that conditions will almost never reach the limits of the unlimited hosting package you are subscribed to.
But when your websites get larger and the amount of traffic they get increase to certain levels, or some web traffic peaks occur due to reasons such as a new product launch or a blog post going viral, you will most probably get notified by your hosting company to upgrade your shared hosting account to a dedicated one. And if you are not prepared to make that investment, you may end up your account getting suspended, rendering your websites offline.
The real limits for the unlimited shared hosting packages may show difference between hosting providers and I highly recommend you read all the related terms before buying web hosting for your website. If you cannot see the real limits, ask them, that is if you have concerns about your website getting higher traffic and reaching the limits.
The below image is taken from a web hosting provider's web hosting plans comparison page. Note the use of the term unlimited for storage and bandwidth:
I am currently hosting my websites including this one with HostGator's shared hosting plan and up to now I did not have any troubles due to web traffic or hosting usage since my websites are not getting much traffic. As I grow my websites and build more websites, I believe I will reach the limits of the unlimited hosting plan one day and I will have to upgrade my account to a dedicated one. Actually, I will be happy to see that since I want my sites to grow and get more traffic, but the point that bothers me is the way the "unlimited" hosting is advertised and the huge price gap between the unlimited hosting plans and the dedicated hosting plans.
The difference is usually over $100 for the most basic dedicated hosting plan, compared to an "unlimited" shared hosting plan. And as you can see from the above image, dedicated hosting accounts have limits. Therefore, if you come to a point that your website grows considerably and requires a lot of resources, then you should start seriously considering setting up your own servers to save a lot on hosting, if you are up for the technical challenge it will present.
Now that you learned that the unlimited hosting plans do have limits as well, you should make your plans accordingly. Watch the traffic level of your website and if it grows too high, you should transfer to a dedicated hosting plan even before they ask you do it because your websites might be taken down if you get a high amount of traffic in a very short time and fail to upgrade in a timely manner.