Web Page Change Detection Resources
ALERT: For an overview and review of Web Page Change Detection Services, review my article, "Do I Detect A Change" that was published in the Fall 2002 issue of Library Journal NetConnect. (Sorry, no longer available online)
What is a Web Page Change Detection Service
A Web page detection service allows an individual to track changes made on a specific web page. This process begins by choosing and subscribing to a change detection service. Then the URLs to monitor are identified. Whenever there is a change to one of these URLs, the detection service will send you an e-mail to notify you of a change. The e-mail will contain a link to the page to facilitate access. Depending on the service you choose there may be a fee or it may be free. If free, the number of URLs you can monitor may be limited or the options for tracking the page may be limited. As with all things, the more you pay (and none of these services is particularly costly) the more you get.
Why is it Mentioned Here
Web page change detection is a powerful tool for supporting a "Keeping Up" strategy. While there has been an increase in the number of e-newsletters you can have "pushed" to your e-mail box, there are still useful web pages that contain information. There are also e-journals that have web sites, but offer no e-mail alerts when a new issue is available. By tracking a page change however, you are usually able to detect those new issues.
How Do I Use Them
They are all fairly easy to use. Once you initiate your subscription, you will create a profile of URLs to monitor. You can add or delete any page at any time. Adding new pages is as simple as typing a URL in a box, and indicating if you want any special options with respect to notification and frequency of alerts. For example, you may be tracking a page that you know changes frequently, but you may set up your profile for weekly notification, so you'll be reminded to visit and review the page for change at least once a week.
What Does it Look Like
Here is an example of what a page change alert looks like. This one is taken directly from an e-mail message I received from the service. Take note of the link in the message that allows me to immediately connect to the web page where the change has occurred.
What Change Detection Services Are Available?
Each of these services has varying features and fees. The best approach is to take a look at each and possibly sign up for a trial to see how well it works for you. The main caution I would offer is that any of these services may fold at any time. You are advised to keep track of all the URLs you are monitoring so that if your service goes out of business, you can quickly migrate to another detection service.
TrackEngine: Found at http://www.trackengine.com/servlets/com.nexlabs.trackengine.ui.Login this is a web page monitoring service with a number of good features - also currently free. This appears to be the best free service available. Of special interest is the icon that you place on your toolbar. Whenever you find a page you want to monitor you simply drag the icon onto the page, and then complete a form. They provide a number of options for customizing the monitoring process.
Watch That Page: Found at http://www.watchthatpage.com is a free service that lets you get your updates by e-mail or they can be posted to a web page. The interface is easy to use, and for a free service the features are relatively decent. They don't specify a limit on the number of pages you can mind. This is probably why it's a heavily used service. Because of that there is sometimes a time lag on getting notified of changes, but you can make a donation to get priority service.
Imorph InfoMinder: Found at http://www.infominder.com this service has features that are similar to Mind-It. Worth considering if you are looking at Mind-It. There is no longer a "free" version, but you can sign up for a 90-day trial that allows you to monitor 10 URLs. The annual fee is less than $24.95 for up to 100 pages monitored, but there are higher priced plans that allow for even more page tracking.
ChangeDetection.com: Found at http://www.changedetection.com/monitor.html, this looks a direct competitor for Mind-It. It is currently free with registration. It offers the basic features of identifying a page, having it monitored, being notified by e-mail of changes, but you cannot (at this time) control the frequency of the alert. Also, you can only register for one alert at a time, so it's a bit clumsy.
Tracerlock: Calls itself "your personal search agent on the Internet." It is found at http://www.tracerlock.com. Its major weakness is that it limits the number of pages it will monitor. This service replaces a totally free service called "The Informant." Informant merged with Tracerlock. This previously free service (if you subscribed while it was free they are maintaining any free alerts) now charges a fee of $48 per year (there are multiple fee-based subscription options).
AlleyCat: Produced by Telatra Research this product seems to do quite a bit more than Web page monitoring, but it certainly features the ability to offer basic change detection alerting. This is software that you load onto your PC. Learn more at http://www.telatra.com/products.html
ChangeDetect Pro: Found at http://www.changedetect.com it offers all of the basic features you'd expect, and does use color codes to show where change has occured on a page. The pricing is based on the number of pages being monitored, and starts at $9.95 per month for 100 pages. There is a free version but it only allows for five pages to be monitored. This is a Web-based service.
Website-Watcher: This is software that you install on your PC, and that gives you the advantage of being able to save content to your hard drive. Otherwise it offers many of the features of the other premium detection services. Pricing starts at $29.95 for the personal edition, and the prices go higher for business and enterprise editions. Get more information at http://www.aignes.com .
Trackle: This is a web-based change detection service. It can check a page for a content change up to 24 times a day. It then sends an e-mail with an excerpt from the changed page in a plain text format. There is a $20 annual fee that offers a maximum of 25 pages for tracking.
Copernic Tracker: This is software that you install on your PC. It monitors web pages and notifies you of change, and the users can set the notification frequency. It can send updates to e-mail, to your desktop, or even to a cell phone. It can be programmed to check for change on any number of keywords on specific pages. As with most installed software for page detection, there is greater functionality. The software sells for $50. There is a 30-day free trial version available.
Wisdom Change: This is a web-based service that is free. The site does not specify any limits on the number of web pages that can be monitored. Registration is fairly easy and add sites to be monitored is also easy - just add the URL in the appropriate space.
Check&Get: This is software you purchase and load on your computer. The cost is $35. It will monitor web sites for change, and retrieves and highlights the changes on monitored pages. You can see screenshots of the software. More information is found at:
Chikaboo: This is a free service that appears to offer the basics. As a web-based service there is nothing to load on your computer. There isn't much information available on the FAQ, but it might be worth a look. It is found at:
URLy Warning: Another software program you load on your computer. The cost is $30. It does most of the usual things that WPCD services do. One interesting feature is that it can announce a change with a pop-up window. More information is found at:
SiteSpector: This too is software that you load onto your computer. The cost is $34.95 for an individual package. Like most programs you install, this one has an impressive array of features and customizations. More information is found at:
Internet Owl: This is a free page change detection service. What makes it a bit unique is that it isn't web-based, but it's software you install. Typically only the web-based services are free. Once the software is installed there is no limit on the number of sites that can be monitored. I have never used it so I can 't comment on its reliability, but it may be worth experimenting with. More information is found at:
http://www.internetowl.com and there is a help page at http://internetowl.com/help/Welcome.html
FeedWhip: This is a free web-based page change detection service. It claims to work with all pages, even those with RSS feeds. They are allowing users to subscribe to an unlimited number of pages, and there are some customizations possible on the frequency of updates and a few other features. I have never used it so I can't comment on its reliability, but it may be worth experimenting with as the number of free, web-based services declines.