Among all the random noise on the web, it can be quite hard to find websites that provide a useful service for free. Can anyone help me catalogue a few, besides the obvious (although maybe there's no such thing as universally obvious)?

http://gethuman.com/ - instructions on how to reach a human operator on several annoying automated customer service lines

http://www.xe.com/ - live conversion rates for all the world's currencies

http://www.bugmenot.com/ - communal logins for various websites that force you to register when you might not want to

I would recommend
http://archive.org this website stores backups of webpages. The massive utility of this site is in its ability to retrieve things on the web that you thought were lost forever. From astoundingly many sites, you can retrieve pages and attached documents that you thought were lost forever. Disclaimer: it runs more slowly, has some broken links and cannot run search bars.

http://www.chacha.com if you're trying to find something on the internet but you're stuck, you can enlist the help of a search assistant for free at chacha.

http://www.google.com is your tech-expert if any piece of technology produces an error, note down the error message, note down the product number of your tech product and enter them into google. Often you will recieve suggestions for what has worked for other individuals from http://answers.yahoo.com/, http://whirlpool.net.au/ or someplace similar.

http://www.photobucket hosts your photos. It's useful to know how to use it or one of its competitors.

http://www.visuwords.coma thesaurus that maps words out with a cool interface

http://www.staticice.com.au,http://www.booko.com.au,http://www.getprice.com.au Find a price search engine for your area. It will save you a lot of money. The preceding sites I use for technology, books and everything else respectively.

Nationmaster.com - Huge source of data and time series for countries.

Zotero.org - Extension for Firefox that does what EndNode does (manage references), but it's free and easier to use.

reader.google.com - if you're not using it to manage your rss feed and internet use yet, you really must start.