The advantage of this may not be immediately obvious.  It’s not a service that (in my opinion) is meant to replace your browser bookmarks.  I use my browser bookmarks for sites I visit on a regular basis, such as Gmail, my online banking accounts, Facebook, etc.  I use Del.icio.us for pages I wish to remember, and maybe access at some point in the future, but don’t need regularly enough to clutter up my browser with them.

If I find a watch I really like on Amazon and may want to eventually buy, I’ll tag it on Del.icio.us.  If I find a tutorial I need to try the next time I have a free moment, I’ll tag that too.  This way, I access Del.icio.us only for sites that are of some use to me but don’t really belong in my daily workflow.  Then I can store as many as I like without worrying about clutter.  And since Del.icio.us offers searching and nested tagging, it’s easy to find and/or browse these pages later.

Del.icio.us offers a bookmarklet – a quick javascript that is stored as a bookmark in your browser.  When you’re on a page, you click the bookmarklet and your browser will automatically load up a form that lets you quickly post it to your Del.icio.us account with no cutting or pasting of addresses.

Which brings me to the good news – your Del.icio.us bookmarklet works on your iPhone.  The easiest way to get it there is to put the bookmarklet in your Safari bookmarks, which are then synced to your iPhone with MobileMe.

That way, if you’ve found a site on the iPhone you’d like to tag, you just open up your bookmarks and select the bookmarklet.  It’ll let you post that site to your Del.icio.us account (you might want to add “iphone” to the list of tags so you can tell which sites you’ve marked on your phone, especially if it’s an iPhone-formatted site) easily, and you can then access that later on your browser or even from your iPhone (bookmark Del.icio.us as well).