Can somebody tell how to change the font size, as my posts seem to be getting more and more difficult to see.
Having said that, this post seems to be in a better size font
There is a tab in the tool bar to the right of the smily face with a drop down menu. I think this defaults to "Paragraph" which seems to be quite a small font. If you select one of the other options in the drop down box you can play around with the size and style of the font
As John said, the small drop down box at the top right of the reply box gives some limited options to alter forum fonts.
It's also possible to make the forum webpage appear to be bigger by holding down the Ctrl key and pressing +which can make the text easier to read.
To make the forum page smaller on your monitor hold down Ctrl and press -