Breaking news: Twitter has gone mainstream. Jimmy Fallon, Shaq, Starbucks, Rainn Wilson, etc, etc, etc are all over it these days. It’s not just a bunch of tech geeks anymore.

Twitter has a big month, grows to over 8 million U.S. users — It wasn’t that long ago that Twitter only had a few million worldwide users. When I joined in 2007, it might have been under 1 million. But Twitter really is going mainstream. Not only does it have millions of users right now, but it’s growing very rapidly.

Last month saw 33% growth in the number of users in the U.S. Twitter is a tool that news organizations need to harness now, because it’s exploding. Don’t wait until it’s too late like we have with other technologies. Also, Twitter isn’t just a bunch of teenagers. The medium age of a Twitter user is 31.

Yes, there is another new Facebook design — Facebook has rolled out yet another new design for its service, and the new look should be showing up on your accounts over the next few days. This one is clearly aimed at Twitter. For content creators, there are a few things to take note of:

With Facebook trying to be more like Twitter and Friendfeed, it’s possible that more conversations may take place on Facebook. This might make Facebook a more valuable beatblogging tool. Also, Facebook now allows you to filter your news feeds. You can stick different contacts into different groups — one for friends, one for work, one for your beatblog, etc — and then view each groups updates individually. This is a nice.

The other new part of this new design is how pages are more like profiles. Many beatbloggers and journalism organizations have tried creating pages or groups in order to harness Facebook as a tool. That just didn’t work that well, because the old Facebook technology was too static. The new pages that news orgs can use look a lot more like profiles, and they gain much of the same functionality.

Check out the updated New York Times’ page. The other huge part of this switch is that items from your pages will begin showing up in users’ news feeds. These changes should make Facebook a much better tool for news organizations and journalists.

Google Reader gets its own comment system — If you’re a journalist and you’re not on Google Reader or a similar RSS feed reader program, what are you doing? Making your life more difficult, that’s what you’re doing. Google Reader now allows people to comment on items they share and then other people can leave comments as well (this is a bit more advanced than the old notes feature). It’s very Friendfeed like, and it’s a very welcome addition.

Reader has gotten steadily more social, and its increasing socialness is making Reader a much more intriguing application. Reader could be an especially good social network for journalists to share information between each other and comment. With the new features, Reader gets my recommendation for best RSS feed reader for journalists.

And yes, you should be using RSS.