If you have a website, it has to be hosted somewhere - which is to say, it has to be on a special computer called a hosting server which is connected to the Internet, and where, you might say, the Internet can find it.
There are thousands of hosting services and many different options. They are not all equal even though they may appear to offer the same service.
One hidden factor rarely mentioned is how many websites does the hosting company put on one server? The more the merrier some believe. It's pure profit since there's basically zero cost on their part to put one more website on a server. But at some point they s-l-o-w down.
Technical competence varies wildly as well often reflected in downtime - and sometimes other issues. Then there is tech support.
A recent example of another potential hazard just hit the news. Federal authorities forced a hosting company to shut down a server with 83,000 blogs on it. Apparently this is part of a criminal case. The point is any server with 83,000 websites on it is probably really cheap (we have less than 100 on ours), plus, most likely the large majority of those websites were completely innocent victims of the criminality of their server neighbors.
It's like living in an apartment building with crack dealers. You could suffer the consequences.
So how do you know if you are in a safe neighborhood? or that the electricity will work or the landlord fix the plumbing when there's a problem?
You can almost guarantee that cheap hosting is going to be bad hosting.
You can look at reviews and reports online about the hosting company.
The best answer is the recommendation of someone who makes his living dealing with Internet issues, such as a professional website designer or IT professional.