Website uptime is a measure how often your website is available to everyone on the internet.  Ideally we are striving for 100%.  Websites are loaded from what’s basically a big computer called a server, and since it’s a computer it occasionally needs to be restarted, updated, etc. in order to continue to function well.  Because of this maintenance 100% uptime isn’t realistic, but somewhere in the 99% or greater range is.  What we are basically looking for here is any red flags where the site is not working for long periods.
I agree with Jeremy. The purchase of the website should really go hand-in-hand with the business startup or company formation. Many startups think it doesn't really matter to get that best domain name, whether it is an exact match keyword, or a brandable name keyword, until after they've started up the business. This is so backwards thinking. Your domain name should be an integral part of your business and development plan, if any significant part of your business is going to come from your online presence. Taken to the extreme, if you are an online marketer, you don't want you domain name to be AppleTurnover.com, because your business premises are in Apple Street. and your company domain is Apple Online Marketing Agents, and AppleTurnover.com (which is anyway surely taken) was the closest name available. It needs careful planning. Of course depending on the size of your business. rgds stu
One downside of most of these services is that, should you someday want to move to another web host, you'll likely be out of luck because of the custom code they use to display your site. Only a few of the services here let you take your site to another web hosting service: The most complete example of this is Weebly, which lets you download the standard site server folders. Squarespace offers some transferability by letting you output your site in standard WordPress format. As you might expect, the same transferability holds for WordPress.com.

WordPress vs. Joomla/Drupal: Drupal is a very powerful platform that is popular with web developers and experienced coders, but it comes with a very steep learning curve that makes it a bad choice for beginners. Joomla is similar to WordPress and works great for online stores, but you’ll need at least a little bit of technical coding to make it work the way you want.
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