Blogs
A blog is a kind of diary - a place to put thoughts & ideas & questions for others to see & respond to. 

You can make these public, private or for logged on users. It's  better to make them public & put in the tags beneath - words that summarise the post you make - so that others can find you through the cloud tag - see the top right of each page. 

So say you have a problem class, you write about it & then others respond.

This is all on a personal basis. Then there are the communities where all can join & there is a communal blog for all to contirbute to. It is a good idea to join the communities you're interested in & post ideas there. 

The rss feeds are for you to keep up with what's happening on websites of interest to you. If there is an rss feed icon on the web page, click on it & you should be taken to a page with a link which you copy & paste into the box on your 'Resourcses' page. Then you can see periodically what's happening on that site by clicking on view link.   

The idea of the site is just as you say - for teachers to exchange ideas. The best way to do this is in the communities.

There is also a file upload space for you to pass on materials to each other. These are both in your personal space & in each community. There is a 10mb limit for each person & each community. It is not a storage facility.  

Hope this helps.