веб сервисы для слежения за обновлениями
It is difficult enough tracking down relevant and useful sites, but keeping up with changes to the pages is an impossible task when you have more than a a dozen or so to monitor. Link checkers such as Xenu Link Sleuth (http://home.snafu.de/tilman/xenulink.html) can alert you to pages that have disappeared or that are redirecting users to another site, but changes to the content are equally if not more important.
There are many services that monitor web page content for changes. Some are free whilst other priced services may offer limited facilities as a free taster.
This review looks at two types of services: web based services and software programs for PCs and Intranets.
Web based services
Change Detection
URL:
http://www.changedetection.com/ This is a free service allowing you to monitor an unlimited number of pages. The frequency of the alerts can be daily, weekly or monthly and you can choose to only have alerts for "sizeable changes", when content has been added or removed, or for specific keywords. The email merely alerts you to the fact that there have been changes; you have to click on a link in the email to view them in the Change Detection web site.
ChangeDetect
URL:
http://www.changedetect.com/ The free trial version of this service allows you to monitor a maximum of 5 pages a week and marks web page text for you with color-coded highlights of what has changed. The free trial lasts for two weeks. You can receive web page change notifications via your email, pager, ICQ or text messaging. The subscription services allow you to monitor more pages and password protected pages. ChangeDetect Personal costs USD 1.95 a month and monitors 10 web pages. ChangeDetect Plus costs USD 14.95 a month for 100 web pages and allows you to set up keyword and phrase notification triggers. ChangeDetect Professional costs USD 39.95 a month for 500 web pages with content checked twice-daily.
ChangeNotes
URL:
http://www.changenotes.com/ Free service that monitors up to a hundred pages and emails changes to you.
Feedwhip
URL:
http://www.feedwhip.com/ Free service that alerts you of changes by email or RSS. The free Basic service only allows you three page monitors and the free 'upgrade' to BasicPlus limits you to ten.
FollowThatPage
URL:
http://www.followthatpage.com/ The free service provides 100 daily page checks and 1 hourly check. You can monitor additions, deletions, Google page rank, keywords, and sections of a page. Alerts are sent to you by email. They say they are working on a paid version of their service that can monitor 1000 pages per day and 50 pages per hour per user.
Infominder
URL:
http://www.infominder.com/ Tracks up to 10 pages free of charge and allows you to associate categories and descriptions with a "minder". Within the advanced options you can specify how often, in days, the page is to be checked. The most frequent allowed for free is every 1 day. You can also specify the minimum number of changes that must occur before you are notified and any keywords or phrases that must appear in the changes.
Infominder Professional, which checks for page changes once a day, costs from USD 30/yr for 100 minders to USD 250/yr for 1000 minders. The Premium version checks pages 4 times a day and prices range from USD 65/yr for 100 pages to USD 500/yr for 1000 pages.
The email notification includes the number of changes that have occurred, the number of characters that have changed and the altered text. There is a link to the Infominder page where you can view a copy of the page with the changes highlighted.
Although the prices have been 'updated' on the site, the repeated reference to support for Netscape Navigator in the FAQs and other pages and no reference to Firefox does not inspire confidence in this service and suggests that its owners have put it on the backburner.
Page2RSS
URL:
http://page2rss.com Page2RSS monitors web pages for changes and notifies you of those changes by RSS. Simply type in the URL of the page you wish to monitor and then add the feed URL to your favourite feed reader. Excellent tool for pages that do not offer their own RSS feeds.
Pagehammer
URL:
http://www.pagehammer.com/ Free service that allows you to monitor channels, or groups of web pages, containing similar content or pages from one particular web site. Each channel can have different monitoring frequencies (twice daily, daily, twice a week or weekly). You can also specify for each page keywords and phrases that are to be specifically monitored or excluded. The email alerts send you new or changed text and also text that has been deleted.
Track Engine
URL:
http://www.trackengine.com/ The free part of this service, which is limited to 5 pages, is a demonstration for the priced version. For each page you can set up an easy to remember name or description and the monitoring frequency (daily, 2 days, 3 days or weekly). The advanced options enable you to select the colour for highlighting the changes on the monitored page, and to track changes to hyperlinks, images, numbers and dates as well as the text. You can request alerts for changes that include specified words or phrases and tell it to ignore certain changes. You can even monitor pages that are password protected by supplying Track Engine with your user name and password. You can upgrade to "Big Breakfast", which costs US $4.95 a month for 50 bookmarks, or to "Just Coffee" at US $19.95 a year for 10 bookmarks.
Watch That Page
URL:
http://www.watchthatpage.com/ This is a free service run by ATS Consulting, a Norwegian company that specialises in software development. You can monitor an unlimited number of pages, which can be grouped into folders and monitored on a daily or weekly basis. There is a keyword matching option that filters the changes that are relevant to you, for example if you are only looking for news where a certain term or phrase occurs such as a company or a product name. Channels enable you to divide your pages into groups based on importance or content type. Each channel can have different properties: some can have keyword matching and daily reports whilst others can be checked less frequently and report all changes. Email alerts can include the text that has changed on your pages or just list the URLs of pages that have changed. If you are a professional or heavy user, you are required to pay a fee. Watchthatpage will notify you by email if you fall into the heavy user category.
Desktop programs
Copernic Tracker
URL:
http://www.copernic.com/en/products/tracker/ Copernic Tracker is a monitoring program that costs US $49.95. Once installed on your PC it enables you to track any number of pages on external sites and intranets. You can track changed words, new links or images. There is a useful advanced query form for tracking specific words within pages, Boolean and other search operators (AND, OR, NEAR).
Copies of page revisions are stored locally so that you can compare changes that occurred in the past and add your own notes for tracked pages and each of their revisions. There is an option for importing favorites from Internet Explorer so that you do not have to key in lists of sites, but no facility for directly importing Mozilla/Netscape bookmarks or Opera Hot lists.
There are four pre-set tracking schedules: Multiple Times per Day, On a Daily Basis, On a Weekly Basis and On a Monthly Basis. Alerts can be a tray icon, desktop alert or notification message, SMS notification, email report with the tracked page contents and changes highlighted.
Internet Owl
URL:http://www.internetowl.com/
Free program. As well as general changes to a page you can monitor the page for the appearance or deletion of specified text, or monitor selected areas of the page. You can view changes from within the program or in your browser and be alerted via email, a pop-up on your desktop or a sound. The default checking frequency - minutes, hours or days - can be changed as can the frequency for individual pages.
Website Watcher
URL:
http://aignes.com/ The full version of this software is available on a 30 day free trial. It monitors an unlimited number of pages and you can choose to ignore HTML tags, images/banners, numbers and dates. You can enter user names and passwords for password protected pages that you wish to monitor. Pages can be checked once a day, once a week, or on a specified day or days of the week. You can even specify the checking frequency during a day either in hours or minutes.
This is the only service that enables you to monitor entire sites without having to specify each page individually (not available in the Basic Edition). As well as web pages you can monitor RSS and Atom feeds, but this feature is not really a replacement for a fully fledged RSS reader if you are a serious news junkie.
Prices are 29.95 Euros for the Basic Edition, 49.95 for the Personal Edition, 99 Euros for a single user Business licence, 1990 Euros for a site license and 9990 Euros for an enterprise licence.
