Solve the Same Problem in Different Environments
To compare a text only discussion forum (Orkut.com) with a graphical discussion forum (Ning.com), it is helpful to observe the same mathematics problem being attempted in each environment.
The problem is:
What is the largest area of the semi-circle that can be inscribed in a square of edge length 1 unit?

Solving the Problem in a Plain Text Discussion
This question was posted by harpreet in the topic " maxima & minima" on a Mathematics forum on Orkut.com on 12th July 2009. (The comment cover two pages, so you need to click Next to go the the 2nd page.) There, you can see that the solution is presented in plain text. It is very difficult to explain the geometry in plain language, and the reader would need to have a good imagination to visualise the explanation. The equations were expressed in plain ASCII text, and are more tedious to read than typeset equations. An advantage of the plain text solution is that it is available to people who are blind or have poor vision. The text could be vocalised or translated to Braille by screen reading software.

Solving the Problem in a Discussion with Embedded Images
I posted the same question "Largest Semicircle Inscribable in a Unit Square" in the Math Problem Solving group on http://mathematics24x7.ning.com/ on Ning.com.
You can see that graphics were used to explain the solution. A diagram of the geometry was presented by uploading an image. The sequence of equations, that lead to the solution, are typeset, which makes them much easier to read than plain text. The typesetting of the equations was done using an online equation editor. An image of the equations was then uploaded into the article. Generally articles that include graphic equations do not include the source LaTeX, so that information is lost, making it difficult for someone else to develop the equations further. In this case, I included the source LaTeX for the equations.

Conclusion
We cannot draw firm conclusions from a comparison of the two forums, because the availability of graphics was not the only difference between them. The members of the Orkut group were students and the members of the Mathematics24x7 group were teachers or graduates. A key question that remains to be answered is: Would the discussion on the Orkut community have progressed further if the participants had had a convenient method of drawing the geometry and rendering the equations?