Jon poined me at an article at MarketingVox reporting on a study coming out of KnowledgeStorm and Universal McCann that indicates that more than 53% of professionals’ purchasing decisions are impacted by content they read on blogs.

A different study by PQ Media shows that ad spending in blogs, podcasts, and RSS feeds has more than doubled, showing that a lot of advertisers are heading where the eyes are going. If you want a short overview of the report, MarketingVox has that, too.

To take this out of the abstract, let’s take a look at RSS and what people are actually doing with it.

• What does RSS actually do? And how?

At the most basic level, an RSS feed is similar to a web page. An RSS reader is very much like your web browser.

Web pages are generally written in HTML (define) which essentially consists of text, pointers to images (and videos and such), and directions for how to lay it all out in a window. Web browsers look at those directions, retreive the images and other media, and draw it all out for you.

RSS feeds are written in XML (define), which is similar to HTML but a good bit more flexible. When used for an RSS feed, the XML doesn’t hold as much information about how to display the text and images. Instead, it tells the RSS reader what sort of information is being provided. The RSS reader then knows how it wants to display that information.

The other difference between a browser and an RSS reader is when it retrieves the file. Your web browser will get the HTML code for a web page when you request the page and then it keeps it in memory for a while. An RSS reader retrieves the XML code for a feed every 5-15 minutes or so depending on how it has been set up. It is constantly updating itself.

• But what is RSS good for?

Because RSS readers are constantly updating their content, they are ideal for publishing changes that are frequent or important to keep subscribers current. Therefore, they are used for blogs, news sites, press release notifications, and any sort of action alerts including sale and coupon notifications.

• I have changes I want people to know about so how does a feed get published?

Most blog software has basic RSS ability built in. Content management software like Drupal and ExpressionEngine also include RSS capabilities. A feed is simply a file, accessible over the internet, in the correct format. You could hand-code a feed if you knew the XML to put in with the text - it’s simply text with tags - but that would be exceptionally tedious and error-prone and it would become overwhelming if you had many changes to publish. A lot of feeds are created by pages coded in PHP (define), a relatively simple language for creating dynamic web pages (compared to earlier scripting languages, it’s not too difficult but it’s still not something I’d try to learn on a Saturday).

If you want to publish a feed, though, and you don’t already know how or have it built in to your publishing software, there’s plenty of help out there. Software to create RSS feeds can be found from Feed for All, Kapow, Software Garden, JitBit, and Reinvented Software among others.

• I have a feed, now what do I do with it?

Well, assuming that you don’t want to simply hope that people come subscribe to it, there are a few places to go to promote it. Some are paid services and some are free. Pheedo and SimpleFeed are two paid services primarily aimed at marketing and advertising. Yahoo! has a feed publisher. If your blog has a feed, Technorati is a good place to go. FeedBurner has services aimed at blogs, podcasts and commercial feeds.

Now, for what other companies have done with their feeds, please head over to ClickZ for a roundup of Real Life RSS Marketing including coupon feeds, affiliate marketing, PR, classifieds, podcasts, and branded informational content. There are some fantastic ideas over there!