Part two of our series on RSS takes a look at the specialized search tools that help you locate content in blogs, feeds and other sources of information.
Note: Part one of this series is What is RSS, and Why Should You Care?
Many people mistakenly refer to RSS search as "blog search." While it's true that many blogs offer RSS feeds (automatic feed creation is a feature of most blogging software), not all blogs have feeds. Furthermore, RSS can literally be used with just about any kind of web-based content. RSS fundamentally is a relatively simple specification that uses XML to organize and format web-based content in a standard way.
While blogs arguably make up the majority of RSS content, many news sites also syndicate content via RSS—for example, Search Engine Watch is available via RSS feeds.
But RSS feeds are increasingly being used for other types of content. For example, you can get RSS feeds with weather forecasts, company news and financial information, package tracking and lots of others. Even the venerable Yahoo Directory is available now through RSS feeds.
Although there are literally millions of feeds available, finding those that are appealing and relevant to you isn't always easy. The major search engines are all dabbling with feed search, but none offer a robust service as yet. And while there are a number of smaller, specialized blog and feed search engines, their lack of resources and the problem of blog and feed spam means their search results are often useless. So finding relevant feeds, at least for the time-being, often remains a hit-or-miss affair.
RSS and Feed Search Engines
Here's a look at some of the better-known players in the blog feed search space. For a more comprehensive list, see Peter Scott's list of RSS search services at his RSS Compendium site.
Bloglines, owned by Ask Jeeves, is both a feed search tool and a feed reader/aggregator. A drop-down menu next to its search form allows you to search all of the blogs it has indexed, only the blogs you subscribe to, the web (via Ask Jeeves), or add a feed to your subscription.
Bloglines' advanced search page gives you basic form-based Boolean capabilities, and also provides filters to sort your results by popularity or date, and to search all blogs, only those in your subscriptions, or to exclude your subscribed blogs when searching.
Bloglines has many other useful features for reading feeds and managing subscriptions that I'll describe in tomorrow's SearchDay, which focuses on feed readers.
Although BlogPulse is known primarily as a tool for tracking trends and hot topics in the blogosphere, it also has a good feed search engine, and depending on the numbers you believe, also has one of the largest indexes of feed-based content of any feed search service.
BlogPulse's advanced search page provides phrase search, all the words or any of the words filters, and even allows you to create your own free-form Boolean queries. You can also limit results to content published within a particular date range, and sort results by date or relevance.
Daypop was one of the first blog/feed search engines, receiving honorable mentions in the Search Engine Watch awards in 2001 and 2002. A one-man operation, Daypop doesn't seem to have the momentum it once had, at least compared with similar services. See Gary Price's interview with Dan Chan, Daypop's founder and proprietor, for a fascinating glimpse behind the scenes of the service.
Daypop's advanced search page provides basic date filters, but also allows you to limit results to a particular language or country, something most other blog/feed search tools do not support.
Feedster offers a number of interesting features, such as the ability to subscribe to a search and save it as a feed, or to have new results sent to you via email. Feedster also lets you search for both items within feeds, as well as feeds themselves, rather than doing a full text search. To find feeds, you can enter keywords, URLs or a combination of both.
Feedster's advanced search page offers the ability to limit your search to just certain feeds or collections of feeds. Additionally, you can filter out certain feeds including your own.
Findory is a news search tool that has a separate tab for blogs. Blogory's main page looks a lot like Google news, with clippings from "top blogs" and links to blogs organized by categories.
Blogory doesn't offer an advanced search for blogs, but it does provide cool personalized, adaptive RSS feeds that automatically find blogs for you based on your interests and other blogs you've read. See my SearchDay story All the News That's Fit For All the News That's Fit For You for more on how this works.
Gigablast Blog Search
Gigablast is a web search engine that also offers blog search. Gigablast's blog search is in beta, but the quality of its results is on par with, if not better than, the results you get with other blog search engines. Although there's no explicit advanced search for blogs, you can use the main advanced search page to narrow your results.
Gigablast also offers an XML search feed service that lets you create your own feed based on Gigablast search results. It's a bit of a geeky feature, but if you want to track results over time using Gigablast it's worth investigating.
IceRocket Blog Search
Like Gigablast, IceRocket offers several types of search results, including web, news images and others. Its advanced blog search page provides both basic Boolean and date range filters, and also offers the ability to search for posts by a particular author, something not found elsewhere.
IceRocket recently announced that it was changing its name to BlogScour. No word on whether the other search services will continue to be maintained.
Among all of the blog and feed search services reviewed here, PubSub is unique, for a couple of reasons. First, you don't directly search PubSub. Rather, you create subscriptions for the search terms you're interested in, and PubSub in turn delivers alerts whenever any new content is found for your subscriptions. Alerts can be delivered via email, SMS, PDA/mobile devices and instant messaging.
PubSub's second difference is that it's a "real-time" search service, meaning you'll get alerts nearly instantly after content has been published. For more on PubSub, see my SearchDay article Managing the Firehose of Real-Time Information
Technorati lets you search by keywords, URL or tags. You can access all of these flavors of search via a single search form and entering your query in the appropriate box.
Not Playing Yet: The Major Search Engines
What about the major search engines? They are all tiptoeing around RSS search, but none have yet to launch a full-blown RSS search service.
Ask Jeeves, as said, owns Bloglines, and in conversations I've had with various key players it's clear that RSS is important for the company. Whether Bloglines expands to include Teoma-like search capabilities, or Ask pulls in Bloglines' RSS prowess remains to be seen. In all likelihood, both services will be enhanced with complementary strengths of the other.
Google does let you search for RSS feeds, but you have to opt to create a customized home page, click the "create a section" link and only then will you see a search form to discover feeds. There's also the undocumented filetype:rss and filetype:xml filters, which can be used from any Google search box. The new Google Desktop Search 2 has an auto-discovery feature for RSS feeds which I'll write more about tomorrow.
When Google purchased Blogger in February 2003 the company stated that blog search was definitely on the radar. Although Google remains mum about its RSS search plans, it's clear that it's coming, and likely sooner rather than later.
MSN Search also does not support RSS searching, but Microsoft is also working with the technology. MSN's experimental Start page now allows you to add RSS feeds; Microsoft also recently introduced a screen saver with RSS integration.
Yahoo is arguably the farthest along with RSS. Yahoo's advanced search lets you limit results to XML, RDF and RSS file types. Feeds can also show up in general search results, and you can add a feed to your My Yahoo page simply by clicking the Add to My Yahoo link in a search result.
I expect full-fledged support for RSS searching from all of the major players by the end of the year.
Now that you've found RSS feeds you want to follow, how do you do it? Part three of this series, Choosing an RSS Reader, looks at the various tools called feed readers and their comparative strengths and weaknesses.