Many of the functions it performs are self-evident, a few are not, and some of the tools are best not used. A description of a tool's function appears if you hover your mouse arrow over the button. Because much of Plone is constantly evolving, the bugs noted below might be clearing up in the near future. Here is a brief synopsis of them, in the order that they appear.
 
These buttons toggle whether the highlighted text is bolded, italicized, underlined, crossed out, super-scripted, or sub-scripted.
   

           This tool (the remove format tool) works only on our newer sites, and only half-way.  If you're pasting content in from Microsoft Word, it will mangle some of the presentation (especially the font).  Try clicking this button to remove the bad formating.  If this doesn't   work, you'll need to paste the content in NotePad (on Windows) to remove all formating and then copy and paste that into the text body.
  
   Text color and background color. Both conjure a color palette from which to choose a color.     The background color function doesn't seem to work.

Text indentation (left, center, right justified). Best used on an entire paragraph.

 
Ordered, and bulleted lists. We encourage you to use these instead of trying to manually insert numbers or bullets. To stop adding items to a list, delete the last bullet/number.
  
 Increase/decrease indent. Best used for excerpted text.

 For inserting a link. Use this for linking text to external URLs (web sites outside of yours).  To remove a link that you've already created, highlight the linked word (or phrase) and create a new link, only leave itblank.
   
For inserting anchors -- links pointing to parts lower down in the same page.  (You can learn more about anchors elsewhere in the site.) 

To insert the anchor, go the part of the page where you want to anchor to (this will be down the page), create anchor text. 

Highlight the text and click the anchor icon, name the anchor. 

Go to the area of the page where you want to anchor from and insert a normal internal link to the page plus the pound symbol (#) and then the name of your anchor. eg /aboutus/ourconference/#speakers
 
This button is for inserting images (although you would never guess it from the icon). Don't use it. Usually it's preferable to use a Page with Pix for managing images, or the toolbox described below.
  
Inserting a horizontal line, and tables. The former is simple; the latter is not. Tables are a little hard to format using this tool (the interface is not very intuitive), although sometimes it is adequate. If you need a complex table, do it in HTML or ask for assistance.
 
This - the toolbox - is the most useful (and cryptically depicted) tool for web editing. It allows you to insert internal links (that is, links to other pages within the site) and images into a page. It's powerful enough that we devote the next page to it.

Undo and redo edits done before the last time you saved. These buttons work with varying levels of success. Note that there is a more involved site-wide undo feature discussed elsewhere.