Once your website is published it is live and up on the internet for anyone to see. The next step is to begin getting visitors to your website, typically this is done through building up links to your website, getting listed on search engines and engaging in a relevant community to spread the word about your website.
There is no limit to the amount of changes you can make before or after publishing, and remember it is unlikely your website is going to get hundreds of hits the moment it is published. Work needs to be put in by you to spread the word about your awesome new website! To find out more about getting visitors to your site, please visit our Search Engine Optimization help section.
You can always take your site offline, however if you need to make major changes, or even make minor additions and touch-up's, you can do this post-publish.