After a vote in cam.misc in late January 1999 conducted by Vicky the following text on posting adverts in the cam.* newsgroups was agreed.
Adverts for events, items for sale which can be bought in person (not by mail), jobs offered and new web sites are welcomed so long as they relate to Cambridge and its environs and are brief. If you have a lot to say put it on a Web page and post a brief ad with a link to that page. Repeat postings of the same or similar adverts more than once a month are likely to be counterproductive and invite abuse. You should continue to read the group after posting as there will very likely be follow-ups in group. Failing to respond to those will not do the product or service you're advertising any favours.
Adverts should be posted to cam.misc only, or cross posted to both cam.announce and cam.misc setting the Followup-To header to cam.misc. If you don't know how to cross post or set up a Followup-To header using your news reader post your advert to cam.misc only.
Advertisers wishing to promote their Web sites would be well advised to arrange for a link from Keith Edkins' definitive Cambridge Web guide.
Another effective way of promoting your site is to include the URL in your signature, so long as your signature remains brief, the usual convention being four lines or less.
You might also like to read Joel Furr's excellent guide entitled Advertising on Usenet: How To Do It, How Not To Do It which explains some of the reasoning behind the policy outlined above.
(For avoidance of doubt: the text above is talking about posting adverts to the cam.* news groups, not to posting adverts in this Wiki. Adverts are not welcomed here and will be removed.)