One of the great things the Internet can do is bring you tip-offs and story ideas. You can find those things by regular trawling of the newsgroups and other discussions, and by checking various websites, but subscribing to relevant mailing lists and ezines (electronic magazines) will bring them to you while you sleep.
Making email work for you
One advantage of the mailing lists is that they tend to be "refereed", or, as we would say, edited. That keeps the level of relevance and civility higher than it is in Usenet. The only disadvantage (and it is worth thinking about) is that your email box will soon fill up with stuff. The answer is to be rigorous about the way you use mailing lists. Sign up, try a list for a couple of weeks, and if it is not either useful or entertaining, unsubscribe.
As you use the web, you will find many sites inviting you to subscribe to their lists. Many companies make their press releases available in this way. It is up to you how useful that is. Always keep the first issue you receive. It invariably contains valuable information on how to unsubscribe (most important) and how to read and search the list's archives.
My preference is for non-commercial lists put together by enthusiasts and obsessives. These come in several variants. In the most simple form, list members simply agree to make their email addresses available so that any contributions each person makes are sent to everyone on the list. Depending on the enthusiasm of the group, this can mean everything from an email once a month to a torrent of postings arriving all day every day.
It often makes more sense to opt for a "digest" version, where that exists. That means the individual contributions are bundled together before they are sent to subscribers. You might receive one or two sizeable emails a week, rather than scores.
These lists are said to be "open", meaning they include content from all their members. . There are also "closed" mailing lists, which are more like traditional magazines: someone owns and edits them. A good example is Tara Calishain's ResearchBuzz, which is a must for anyone seriously interested in using the Internet for research.
If you want to track down a list on a particular subject, there are various directories and "lists of lists". At one stage there were lots of these but most seem to have disappeared. Try TILE.NET.
In recent times, the role of the email newsletter has been overtaken by RSS technology. This is a way of tracking changes on web pages from your browser. If a site has a "RSS feed", you will see a little logo to that effect either in the title bar of your browser or on the site's home page. If you click on that link, you can add the site's feed to your bookmarks, and you will then be notified every time any new content is added. You can have as many RSS feeds as you like, but checking them every day can be time-consuming.
I also use WatchThatPage to keep an eye out for changes in webpages that do not offer an RSS feed. You have to register, but it costs nothing.
You can also get Google to do regular searches for you, based on queries that you specify. I prefer to use GoogleAlert, which does the same job without being part of Google.