This is something that's been going on for a while - Google killing small web apps; Convertors, calculators, movie listings, ip finders, weather stats, stocks. It's not all low-hanging fruit. I'm not saying they shouldn't be doing this, nor that it's intentional. Their goal is to be the best search engine which means connecting searchers with answers as quickly as they can. But even so, it sucks for the web apps who get made redundant by Google.
Also, it's interesting to compare this with, say, Yahoo's approach. Yahoo would have put an "IP" widget and a "weather" widget on their portal homepage. Google waits until the user searches for the info before giving it to them - which keeps their homepage clean and more importantly keeps their message strong "we do search well", while Yahoo's always seemed to be "we do a whole bunch of stuff, some of which you may need". I know Google/Yahoo comparisons aren't really du jour, but still it's interesting.
This is why I mentioned that it's not all low hanging fruit. Movie listings? Requires feed integration, handling a lot of data, non-trivial presentation. Same with weather. Getting a good weather app is not 10 seconds of coding. Some, like ip address, are simple things, but even so whatismyip.com built a huge range of products around that one simple service.
I always hated how weather sites could not just detect my approximate location based off of ip (eg weather.com) and required me to enter in my zip code, google fixed that.
Pretty sure they got that after google. For years, wunderground was the best of a bunch of terrible web sites. They're still about 40% ads by pixel though, and have a hugely cluttered UI. I'll use them as a second step (Google's "detailed forecast" link) after typing "weather" into the chrome address bar. But broadly, they still suck compared to Google.
Actually the only way for a "my IP" application to make some money is be indexed as first result in Google I guess. At least I never remember the domain of one of that 200 trivial apps and search on google. So makes a lot of sense they showing you the result if you search for "ip" or "my ip".
I bet some of them find alternative ways to get visitors and that a decent number of people use the bookmark feature. Now, how valuable a visitor is to a page like that is another matter.
with the more significant things like movie listings, weather..... it's about Google + the world's information. They want it to flow through them/be indexed by them/found and offered up by them
It still disadvantages those people who want to use that service while there is nothing to perform the job. Take google recently killing code search http://googleblog.blogspot.com/2011/10/fall-sweep.html. One of the commenter's had been building their own code search platform before google did. Google entering the market meant that this was no longer viable though http://news.ycombinator.com/item?id=3112444. A new code search platform will no doubt pop up, but it will take a while to get something that works well.
This is the problem with the giant company stepping into new areas, it often leaves destruction in its wake.
Also, it's interesting to compare this with, say, Yahoo's approach. Yahoo would have put an "IP" widget and a "weather" widget on their portal homepage. Google waits until the user searches for the info before giving it to them - which keeps their homepage clean and more importantly keeps their message strong "we do search well", while Yahoo's always seemed to be "we do a whole bunch of stuff, some of which you may need". I know Google/Yahoo comparisons aren't really du jour, but still it's interesting.