The Google Search Engine is probably the top wonder in the Internet world.  Why, because it’s just so friggin’ huge!  But, also because it involves Google Maps, is integrated with gMail and well, is just a better engine than the other’s.  

Wikipedia – and don’t forget specialty wiki’s like http://starwars.wikia.com/wiki/Main_Page or even (as depressing as it may be) the wikia 90210 page.

Social Networks – Facebook, MySpace, Classmates.com and LinkedIn – oh and digg and delicious too…  Social networks are today’s iteration of what we thought virtual reality would be.  They get better every year, with the exception of New Facebook, which isn’t actually as cool IMO as old Facebook.

Free email – Be it Hotmail (which to me is the original), Gmail or Yahoo mail

E-commerce – Amazon.com, Buy.com, eBay, online banking and one of the best ever (because it’s free), CraigsList.

Peer-to-Peer networks – Torrents, Tor (OK it’s a stretch to call it P2P), etc.  I mean, really…

Wait – that was only 6…  Well, let me know what you think should be number 7.  ;)