Some companies provide free web site hosting to customers with some conditions and restrictions, like advertisement support free web site hosting, or non garanteed web site hosting, or very limited available resource, like storeage space / web space, network bandwidth, limited tooles, CPU cycles, even total number of files. 

Normally, these companies hope that the customers will purchase a paid service after a period of time for their increased demands.  This can happen when the customer get more serious and need better reputation, or the customer need more resouces like storage space or network bandwith.

So, if anyone wants to try some free web hosting first, he should choose those reliable companies, like Go Daddy .