At its most basic level Del.icio.us is a great idea. How many times have you lost your bookmarks when you moved to a new computer or your profile became corrupted or you switched browser?

Del.icio.us gives us a central online repository for storing our bookmarks so that we never lose them again. It also allows us to tag our bookmarks to make finding them subsequently easier.

However, Del.icio.us takes this concept a couple of steps further – in the first place, with Del.icio.us, everyone can see everyone else’s bookmarks and tags – this incredibly simple twist makes the site far more useful – it now becomes possible to see what people are bookmarking on any given topic and since you only bookmark sites which are important/useful – Del.icio.us becomes a phenomenal filter for what is good on the web.

If they had stopped there, it would have been a great site! It gets even better, though! Del.icio.us has a service, rather confusingly called Inbox, which allows you to set up a search for terms of interest and it then gives you a list of all the latest bookmarks corresponding to your search term.

Even better than that again – you also get an rss feed for your Inbox subscriptions – so you can view these bookmarks in your rss reader – how cool is that?

I know several people who use Del.icio.us and who were completely unaware of this – are there other awesome features in Del.icio.us (or other social software apps) that are not obvious?