Not only should the web host be reliable and fast, it should guarantee its uptime (the time when it is functional). Look for a minimum uptime of  99.5% or higher.  Note though that guarantees are often hard to enforce from your end - the host usually requires all sorts of documentation. However, without that guarantee, the web host will have little incentive to ensure that its servers are running all the time.

Data transfer (sometimes loosely referred to as "traffic" or "bandwidth") is the amount of bytes transferred from your site to visitors when they browse your site.

Don't believe any commercial web host that advertises "unlimited bandwidth". The host has to pay for the bandwidth, and if you consume a lot of it, they will not silently bear your costs. Many high bandwidth websites have found this out the hard way when they suddenly receive an exhorbitant bill for having "exceeded" the "unlimited bandwidth". Always look for details on how much traffic the package allows. I personally always stay clear of any host that advertises "unlimited transfer", even if the exact amount is specified somewhere else (sometimes buried in their policy statements).

In addition, while bandwidth provided is something you should always check, do not be unduly swayed by promises of incredibly huge amounts of bandwidth. Chances are that your website will never be able to use that amount because it will hit other limits, namely resource limits.

To give you a rough idea of the typical traffic requirements of a website, most new sites that are not software archives or the like use less than 3 GB of bandwidth per month. Your traffic requirements will grow over time, as your site becomes more well-known (and well-linked), so you will need to also check their policy for overages: is there a published charge per GB over the allowed bandwidth? Is the charge made according to actual usage or are you expected to pre-pay for a potential overage? It is better not to go for hosts that expect you to prepay for overages, since it is very hard to forsee when your site will exceed its bandwidth and by how much.

For the same reason as bandwidth, watch out also for those unlimited disk space schemes. Most sites need less than 10 MB of web space, so even if you are provided with a host that tempts you with 200 MB or 500 MB (or "unlimited space"), be aware that you are unlikely to use that space, so don't let the 500 MB space be too big a factor in your consideration when comparing with other web hosts. The hosting company is also aware of that, which is why they feel free to offer you that as a means of enticing you to host there. As a rough gauge, thefreecountry.com, which had about 150 pages when this article was first written, used less than 5 MB for its pages and associated files.

Does its technical support function 24 hours a day, 7 days a week (often abbreviated 24/7), all year around? Note that I will not accept a host which does not have staff working on weekends or public holidays. You will be surprised at how often things go wrong at the most inconvenient of times. Incidentally, just because a host advertises that it has 24/7 support does not necessarily mean that it really has that kind of support. Test them out by emailing at midnight and on Saturday nights, Sunday mornings, etc. Check out how long they take to respond. Besides speed of responses, check to see if they are technically competent. You wouldn't want to sign up for a host that is run by a bunch of salesmen who only know how to sell and not fix problems.

If you are paying for a site, you really should make sure you have all of these. Note that some commercial hosts do not allow you to install PHP or CGI scripts without their approval. This is not desirable since it means that you have to wait for them before you can implement a feature on your site. ".htaccess" is needed to protect your site in various ways (such as to prevent bandwidth theft and hotlinking, etc). Telnet or SSH access is useful for certain things, including testing CGI scripts, maintaining databases, etc. Cron jobs may be needed for programs that you need to be run periodically (eg once a day). Check to see if these facilities are provided.

If you are planning on doing any sort of business through your website, you might want to look out to see if the host provides these facilities. These facilities normally involve a higher priced package or additional charges. The main thing is to check to see if they are available at all before you commit to the host. You will definitely need SSL if you plan to collect credit card information on your site.

If you have your own site, you would probably want to have email addresses at your own domain, like This e-mail address is being protected from spambots. You need JavaScript enabled to view it , etc. Does the host provide this with the package? Does it allow you to have a catch-all email account that allows This e-mail address is being protected from spambots. You need JavaScript enabled to view it to wind up being routed to you? Can you set an email address to automatically reply to the sender with a preset message (called an autoresponder)? Can you retrieve your mail with your email software? Can it be automatically forwarded to your current email address?

This is called various names by different hosts, but essentially, they all allow you to manage different aspects of your web account yourself. Typically, and at the very minimum, it should allow you to do things like add, delete, and manage your email addresses, and change passwords for your account. I would not go for a host where I have to go through their technical support each time I want to change a password or add/delete an email account. Such chores are common maintenance chores that every webmaster performs time and time again, and it would be a great hassle if you had to wait for their technical support to make the changes for you.

For those who are thinking of selling web space or having multiple domains or subdomains hosted in your account, you should look to see if they provide this, and the amount extra that they charge for this (whether it is a one-time or monthly charge, etc).

Is the type of operating system and server important? Whether you think so or not on the theoretical level, there are a few practical reasons for looking out for the type of server.

In general, if you want to use things like ASP, you have no choice but to look for a Windows NT/2000/XP machine for your server.

Otherwise my preference is to sign up for accounts using the often cheaper, more stable and feature-laden Unix systems running the Apache server. In fact, if dynamically generated pages that can access databases (etc) is what you want, you can always use the more portable (and popular) PHP instead of tying yourself down to ASP. Another reason to prefer Unix-based web hosts (which include web hosts using systems like Linux, FreeBSD, OpenBSD, Solaris, etc) using the Apache web server is that these servers allow you to configure a lot of facilities that you typically need on your site (error pages, protecting your images, blocking email harvesters, blocking IP addresses, etc) without having to ask your web host to implement them.

I was actually hesitant to list this, but I guess it's futile not to. However, I would caution that while price is always a factor, you should realise that you often get what you pay for, although it's not necessarily true that the most expensive hosts are the best.

Most web hosts allow you to select an annual payment plan that gives you a cheaper rate than if you were to pay monthly. My current personal preference is to pay monthly with all new web hosts until I'm assured of their reliability and honesty. Paying monthly allows me to switch web hosts quickly when I find that the current host does not meet my requirements: this way, I'm not tied down to a bad web host because I have prepaid for an entire year. I do this even if the new web host guarantees that they will refund the balance if I'm dissatisfied, since at the point I sign up, I have no assurance that they will honour their guarantee. Later (usually after many months or even more than a year), when I'm satisfied with the host, I often change payment plans to the discounted annual plans.

Not all hosting companies own or lease their own web servers. Some of them are actually resellers for some other hosting company. The disadvantage of using a reseller is the possibility that you are dealing with people who don't know much about the system they are selling and who take longer to help you (they have to transmit your technical support request to the actual hosting company for it to be acted upon). However, this also depends on both the reseller and the underlying hosting company. It is thus wise not to rule out all resellers; there are a number of reliable and fast ones who are actually quite good and cheap. In fact, a number of resellers sell the same packages cheaper than their original hosting company. If you find out that a particular company is a reseller, you will need to investigate both the reseller and the real hosting company.

You have the option of hosting your site with some local provider. The advantage here is the ease of dealing with them (they are after all easily accessible by phone call or a visit), your familiarity with the local laws and easy recourse to those laws should it be necessary. Also server maintainance (which probably will bring your site down) is mostly scheduled at the (local) nightly hours. It should be your choice if your target audience is local (eg a local pc business). On the other hand, in case most of your customers reside in for example the USA, hosting your site in the USA has the advantage of faster access for customers.