Deja.com (formerly known as DejaNews) is the best-known and largest database of Usenet news postings, with articles back to 1995. In 1999, Deja.com added product reviews to its Usenet database and has dropped using the term "Usenet" in favor of "discussions." In Spring 1999, it added a current awareness service along with the name change from Dejanews to Deja.com. In May 2000, the Usenet archive older than May 1999 was dropped, but it is supposed to be available again before the end of 2000. Use the table of contents on the left to navigate this review.
NOTE! On Feb. 12, 2001, Deja.com died. Google has bought the domain names and database and has a searchable database of Usenet postings from Aug. 2000 to the present, but no posting, browsing, or advanced search capabilities. Stay tuned for a full review or see the Google Groups site, their press release, or Google Groups Usenet Help file for more details. In the meantime, this review reflects what Deja used to offer.
Databases:
Deja.com offers more than its Usenet news (or discussions) database. It also offers product ratings from consumers, or at least a self-volunteered subset of consumers who are willing to post their personal reviews and opinions of products and services at Deja.com. The initial Deja.com page used to give the option of searching either database, but now that option is only available on the Power Search screen and a simple search retrieves results from both databases. The default search and followup searches typically only search the past several weeks. Use the Power Search to search the full archive.
Partners: See the Deja.com Partner List.
NOTE! On Feb. 12, 2001, Deja.com died. Google has bought the domain names and database and has a searchable database of Usenet postings from Aug. 2000 to the present, but no posting, browsing, or advanced search capabilities. Stay tuned for a full review or see the Google Groups site, their press release, or Google Groups Usenet Help file, for more details.
Strengths:
* Largest and oldest collection of Usenet discussions
* Powerful search features
* Can read and post news
* Personal opinions
Weaknesses:
* Personal opinions
* Can be confusing to new users
Default Operation: Multiple search terms are processed as an AND operation by default.
Boolean Searching: Deja.com supports full Boolean searching but not with the usual operators. Study their Search Language Help for all the details. Basically, it requires using & for AND; | for OR; and &! for NOT. Searching can be nested using parentheses. Multiple search terms are processed as an AND operation by default. NOTE that the English language Boolean operators can not be used. Use the symbols instead.
Unique: Deja.com supports using braces { } to search a range. For example {acetylcarnitine acetylene} searches everything that falls alphabetically between acetylcarnitine and acetylene.
Proximity Searching: Deja.com offers both phrase searching and proximity. Phrase searching can be designated by double quotes "like this" around a search phrase. Truncation symbols should not be used within phrases. The ^ symbol is used for proximity searching and equates with a NEAR operator. Add a number after the symbol to specify how far apart the words can be. For example, ^12 means the terms need to be within 12 words of each other. Using ^ without a number defaults to ^5. The ^ symbol should not be used with a phrase search.
Truncation: Deja.com has two truncation symbols. The unlimited truncation symbol is an asterisk *. The question mark ? represents any single character. An unusual addition is the range truncation. Use square brackets [ ] to identify a series of options. For example June 9[678] should find June 96, June 97, as well as June 98. The range of options in the brackets can be numbers or letters. The symbols can be used after only two characters. They can be internal or end truncation but can not be used at the beginning.
Case Sensitivity: Deja.com is not case sensitive. All search terms look for a match regardless of upper and lower case.
Field Searching: Field searching is available in the Power Search or by using the the following field search syntax. Leave a space after the field designator as in the following examples although a space is not required when the search terms are enclosed in parenthese. See also Deja.com's explanations and restrictions
| Field | Explanation |
|---|---|
| ~a | Author search. Looks for the given elements within the poster's email address. ~a ("edward abbey" | monkeywrench@* ) |
| ~s | Subject search. Checks for terms in the subject line of the message. ~s (ibm & layoff) |
| ~g | Newsgroups. Restrictions to hits in newsgroups matching a given term. ~g comp.infosystems.* |
| ~dc | Date created. Use dates in the format of yyyy/mm/dd. ~dc {1995/04/01 1995/05/01} searches between April 1 and May 1, 1995. |
Limits: The Power Search includes several limits. The regular search by default limits to recent articles only. The Power Search covers the whole archive and offers an option to limit to complete, standard, adult, jobs, or for sale portions of the database.
Available language limits include
- Chinese
- Danish
- Dutch
- English
- Finnish
- French
- German
- Hungarian
- Italian
- Japanese
- Korean
- Norwegian
- Portuguese
- Polish
- Russian
- Spanish
- Swedish
- Vietnamese
Stop Words: Deja.com does have a stop word list. See their stop word documentation for a list.
Sorting: By default, hits are sorted by relevance ranking. In the Power Search, results can also be sorted by subject, forum, author, or date.
Display: The display includes the date, subject, forum, and author. Deja.com displays 25 hits at a time, but in the Power Search it provides options for 50 or 100 as well.
Documentation:
Searching Help
Power Search Help
Search Language Help
Press Releases
See also my article "DejaNews and Other Usenet Search Tools".