Google Labs has been putting together some great new search technology lately. They just introduced Social Search, and now the Similar Images feature has graduated from Labs and become a permanent part of Google Image Search. When you search for an image, you'll see "find similar images" links below most of the results: clicking it gives you a pretty accurate collection of images of the same subject.

I tested out similar images on some easy stuff (umbrellas) and some tougher stuff (celebrities), and found that it worked really well. Similar Images is good at matching backgrounds, and even manages to find similarly-posed photos if you're searching for an animal or a person. It obviously doesn't do as well when the subject is obscure or abstract, or there aren't a lot of photos of it in the database. In cases like that, it'll be more likely to match your image's color scheme than to find a picture of the same person or thing.

Similar Images isn't made to find identical images hosted on different sites. If you're trying to determine where an image came from, try putting it into TinEye instead.

Last week, at the Web2.0 Expo, Google demoed a new Social Search feature that delivers targeted search results based on your social circle. Now, this feature is available in Google Labs, so anyone with a Google account can try it out. When social search gives you "results from your social circle," who does it mean? Google looks at your Gmail chat buddies and contacts, as well as your Twitter and FriendFeed buddies and your Google Reader subscriptions to find relevant results. So far, it doesn't seem like Social Search is for everyone, but you should definitely give it a look if you're a social networking junkie.

Social Search results show you which of your connections a particular result came from, and how you're connected to that person. For example, I searched for Download Squad, and found a blog post from fellow Squadder Nik Fletcher, who I follow on Twitter. Results aren't limited to direct connections, though, Social Search also finds more obscure stuff, like your friends-of-friends on Flickr. It's clearly still a work in progress, but right now it's great for finding blog posts by people you know, and keeping up with your friends across the various networks they're signed up for.

Google has decided that you're not getting enough news in your balanced diet of information. Equatable to hooking up an IV of coffee to get your necessary caffeine, Google Fast Flip, a new Google Labs project, aims to provide you with more news than you probably want, faster than you probably want it. Fast Flip provides a magazine-ish interface to news stories from (currently) three dozen popular news publishers.

You can flip through news articles based on popularity, news sections, hot topics, or publishers. On the home page, you can scroll through a strip of stories to find the first one you're interested; once you've selected a story, you can use the big left and right arrows on either side of the story to go to the previous or next story in the section. You can also scroll through the section's stories using a pop-out sidebar on the left side of the page. Also, the iPhone and Android versions let you actually flip through the stories using touch gestures, making the whole experience more fluent.

Google makes loading the news stories faster by caching them as images; this way, to read a news story, you don't have to load the entire publisher's web page (with all of its graphics and other elements) making load times significantly faster. Instead of having to wait ten seconds for a news site's page to load, the next story's screenshot has already been downloaded and cached in your browser.

Fast Flip also provides recommended results for anyone with a Google Account; it can automatically track the stories you read as well as base recommendations on articles you click the "Like" button for.

Gmail has been supporting IMAP for almost exactly a year now, and they're celebrating by fixing the only thing I don't like about it! One of the latest brilliant ideas to come out of Google Labs is an advanced IMAP controls option that lets you mark messages for deletion without actually deleting them, and send your deleted messages to the trash instead of archiving them, Most importantly, you can hide individual Gmail mailboxes from your IMAP mail client. That sounds like a picky thing, and not really a big deal, but it's actually huge for me.

You may have noticed that Gmail has a mailbox called All Mail, that does exactly what it says -- it keeps copies of all your mail. This is fine if you're using webmail; you don't have to look at it, but it's there when you need it. If you're using an IMAP client, though, those extra copies of every last message in your account get synced to your computer all the time. Why bother downloading an email message twice, especially if you've got an overflowing inbox?

The thing is, now you don't have to. Turn on the advanced settings by going to "settings" and then "Labs" in Gmail. Once you enable the option, go back to settings and go to labels. All it takes is one checkbox, and All Mail will leave your email client alone. Brilliant. Of course, there might be a good reason for wanting to sync All Mail ... I just haven't found it yet. So thanks, Google, for fixing one of my pet peeves!

Google Notebook, the new product Google was being a bit coy about last week, is now up and running, and I have to say I'm pleasantly surprised. When some screenshots surfaced last week it wasn't clear just how Google Notebook would work, but luckily my initial suspicions were confirmed: Google Notebook is powered by a Firefox extension an addon for Firefox and IE. Basically, Google Notebook is similar to the ScrapBook extension, but combined with an Ajaxy web service. It lets you grab web pages, text excerpts, and images and save them to Notebooks. The extension's main interface is a box that pops up in the lower-right corner when you click on "Open Notebook" in your status bar or right-click on something and click on "Note this." When you do so, an editing field pops up where you can type anything you want or drag-and-drop text and images to it. If you've made a selection on a web page when the box pops up, it will automatically be added to your new note. From this interface you can also see the contents of all of your notebooks, create new notebooks and sections heading, and edit previous notes. The little box also links to Google Notebook's "full page view," i.e. the full-fledged Ajaxy web service I mentioned. Anyone who has spent some time with Gmail, Google Calendar, or Google Reader will feel right at home with the interface. The web interface is like a bigger version of the extension's interface, allowing you to delete notes, do more editing (the extension only has buttons for bold and italic, but the web interface has full-fledged rich text support), rearrange notes, and even entire sections by drag-and-drop, and change your sharing preferences (here's an example of a somewhat eclectic shared notebook). You can also select multiple notes using the familiar Shift and Ctrl keys to do batch deletes or moves.

I think that people will find a lot of different uses for Google Notebook. It could, of course, be used as its name suggests, for taking notes and doing research. Others will use it to make collections of links to share, e.g. teachers who want to give their students an annotated list of resources. It might also make a nice way to keep a wishlist. Some will use it to keep track of bookmarks, but it really isn't suited (and doesn't aim) to replace the likes of del.icio.us. Google Notebook lets you search your notes, and having separate notebooks and sub-headings will be enough organization for some people, but the lack of any kind of tagging make it poorly suited for managing a hodge-podge of a few bookmarks. Google Notebook does have a social aspect, though, in the form of a not-yet-implemented global search for searching everyone's publicly-shared notes, but it is primarily a personal tool like Google Calendar. Currently Google Notebook is missing a couple of things that I believe are crucial for its success, namely RSS feeds and an open API, but given Google's track record, I think it's fair to assume that these are on the way and I can't wait to see what people can accomplish with them. I'm also still expecting Google to integrate Google Notebook into Google Toolbar at some point, but since it still lives under the Google Labs banner ("Labs" is the new "Beta"!) they may wait until it's a more proven product.

[Thanks, Bill!]