Here are 5 rules you should follow to find a perfect domain for your website, especially free hosting sites.
Rule #1: Use meaningful words, or keywords in your niche.
Meaningful words are easy to memorize. Your free hosting service need new users, and retain users. If the words used do not have any meaning, the chance is that the user may forget your website. Do not expect them to dig their email for your domain name.
Also, try to use simple words. Remember the native language of most of your users is not English. You are not Google, not Yahoo. Most users will not try to figure out the meaning of your domain name if they do not know the meaning. You may use simple words related to your service. For example, if you are going to provide free forum hosting, you may include bbs or forum in your domain name. The main purpose of including keywords in your domain name is not for memorizing, but for SEO.
Rule #2: No hyphens.
It is very common you find out all combinations of your desired words were registered. Every second, tens of thousands domains are registered. So, some domain registration system will suggest some words with hyphens.
Try to avoid such domains. Firstly, do not expect users to remember hyphens. Secondly, it signals the users that there is a direct competitor, which has longer history and track record, although this is not necessarily true.
Rule #3: No pure numbers.
Most people even cannot remember home number. How can you expect them to remember 6 or 7 digits number (most 3, 4-digit numbers have been registered)?
It seems some Asian webmasters like numbers, possibly because they have better genes with numbers. Anyway, unless your free service is targeting Chinese or other Asian users, you should also avoid pure numbers. No more than 3 numbers in your domain.
Rule #4: Dot com matters.
There are many domain extensions, or top-leve domains (TLDs) or country code TLDs. Usually your first choice of .com was registered already. So, most domain registration system will recommend you other TLDs.
Try to avoid any other TLDs if you are going to use it for your free hosting services. Occasionally, you may use .net or .org if .com was taken. Or, if your targeted users are in a specific country, you may use county code TLDs.
Never use .info for your free hosting service. Due to the promotions of .info domains, most users do not trust .info domain much. Also, as a lot of spammers, and phishing sites are using .info, your email from .info domains may have higher risk of being marked as spam in most email systems.
Rule #5: Know cultural differences
Be cultural sensitive. Try to avoid controversial or vulgar words. Unless your free service is targeted for specific countries or regions, you need check the words used for your domain carefully. Use Wikipedia or some other references to fins out whether the words have special meaning in other countries or cultures.
If you follow these 5 rules, I am sure you will find a perfect domain to start your free service. It will be costly if you have to change domain names later.