Another pull method is the well known bookmark. What's New page, simply bookmark it. Of course, it then becomes your responsibility to go back to the site again and again. There has been much talk recently about push technology and software, but the best technology for this at present is still email. URL-Minder is an example of how email helps turn pull into push.
Direct push depends on the site.
If you find a site that you are interested in and it offers you email updates, by all means take advantage of this feature. It allows you to make the Net work for you. A few examples will show this. If you wanted to keep current on everything new at this site, you would have to mind many pages. CNS will even create a user web page that will provide those updates in addition to, or instead of email notification.