Google, how good you have been to me. They came out with one of the best search engines currently available, and pretty much everyone uses it. The term google is so widely usedthat it is even part of the English language.
Webster's dictionary defines googling as "to search for information about a specific person through the Google search engine."
Great, they got a nice easy to use search engine, how could they possibly top that? Then, they came out with
Google News which aggregated hundreds of news stories from all around the world to one site. This is good because it gives you many perspectives on the same story.
Then there was
GMail which is Google's free e-mail service. It blew away its competition by offering 1 GIGABYTE of space for e-mail. Their unique approach is that they encourage you to keep all your e-mail, and use their search engine to search and find your e-mail messages. Google was able to generate some hype by making GMail an invitation only service initially. Some people were trading GMail invites as currency almost.
Want a free GMail account? Send me a message, to get your free account. Please attach your name and your current e-mail address. I have 50 GMail invites to give away. * A skill-based question may be asked before you collect your prize

.
Okay.... three smash hits, Google can't POSSIBLY top that! I was pleasantly proven wrong with
Google Maps. It sports some pretty sweet features. You enter in an address in plain text, and it can lookup that location for you. Need driving directions, no problems, put in a second address and you've got the directions, and an estimated time of arrival.
Those features are pretty standard for maps, but here's the ones that really jumped out. Today I was confirming directions to Colwood Pentecostal Church, and decided to use Google Maps. So, I merely type in their address, and Google displays their location, and figures out that it is Colwood Pentecostal, and gives me a link to their website. That is pretty neat that Google derived the name of the building I was going to, and its website from a mere street address that I put in.
Other awesome features is the ability to move around the map without having to reload the webpage. You can zoom in, zoom out, move any direction around the map, and the website doesn't have to reload at all. (Normally on most websites, when you click on a link or something, the whole website has to reload.) This ability was usually restricted to Flash applications or Java applets, but most sites don't use those because they require plug-ins, so you have to have something installed on your computer to get Flash or Java to work. Not Google Maps though, you don't have to install anything to get it to work.
The ability to change content on your screen without reloading the webpage is amazing. If you were to tell me that this was possible two or three years ago, I probably would have said you're crazy and you don't know what you're talking about. Google has definitely pushed the envelope in this. As a web developer, I look at this web application and thought, I must strive to be able to do this. They've set the bar pretty high.
Hopefully this spurs more creative ideas in the web development community. It definitely pushes the boundaries of what is possible on webpages using mere HTML and Javascript.
If anyone is geeky enough to want to know about the technical details of Google Maps, there's a pretty good write-up about it
here.