Note: Safari now has this feature — just look in the File menu. For more features check out this Safari Extension.
One feature that Safari lacks is the option to email a web page to someone. This can easily be done by creating a bookmarklet to place in the bookmarks bar.
Now drag the globe icon at the start of the URL to the bookmarks bar, and name the bookmarklet "Mail this page" or something similar. When you click it, your email client will open with a new message containing the web address and the title of the web page. Now all you need to do is choose who to send it to.