Hot answers tagged usenet
The most widely-used is probably Google Groups, which describes itself as a "searchable archive of more than 700 million Usenet postings from a period of more than 20 years."
Do you know the Open-News-Network? They have Webnewsreaders. Not sure if it's what you're looking for.
There is something like NewsReader.com but its paid. Personally I have never tried it, so I cannot really recommend this site.
There seems to be no way but to manipulate the URL. The part of the URL after the last / is the group name. So to view the com.os.linux group, you would enter http://groups.google.com/forum/#!forum/comp.os.linux in the browser's address bar. If you're using Chrome, you could add a "search engine" that allows you to go straight to a Usenet group: ...
You might have luck searching from another search engine, such as http://www.binsearch.info/ Unfortunately it only goes back 900 days, but perhaps that's enough?
If I understand your question, you want to read news such as Usenet News. One way to do that is to install software on your PC that directly connects to a NNTP server. There's a long list of such software at Wikipedia: "List of Usenet newsreaders" and Wikipedia: "Comparison of Usenet newsreaders".
I know that Marc Smith did research into analyzing and visualizing newsgroup activity while he was at Microsoft Research. I don't think it was a webapp, but it was called "Newsgroup Clouds". I have no idea how he gathered the data for analysis -- if he was subscribing to the feeds over time, or if he could analyze a new newsgroup on demand.
Google Groups let's you read and write to most newsgroups, give that a try.
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