The first question I have to ask is why? Usually, the technology follows what you want to do. It depends on the context. As a former Social Studies teacher, I think I'd prefer to tackle the topic of racism personally and not do it using technology...unless there was a good reason for it.
Here's an excellent site--may get you started. You'll find a wealth of ideas and resources here--
Teaching tolerance: http://www.tolerance.org/index.jsp
I agree with Joel and Kelly, there are pitfalls in doing this online. There was a lesson at teaching tolerance though, that may have online applications. It was about shared anonymous journals. The students would be anonymous to each other (not to the teacher), and would read each others' journals (and the teacher would monitor them as well). This was intended to reduce bullying. It would also give lessons on tolerance if you have a mixed race/ethnicity school. I could see this also being done online in a blog or discussion forum.
Here it is: http://www.tolerance.org/teach/activities/activity.jsp?ar=783
I guess I wonder how the issue of racism or any -ism can be done comfortably? Usually any discussion of this sort has built in uncomfortableness as it makes us look inward at ourselves, something that many people are not comfortable at doing. Racism takes place in many ways and in many forms. To be proactive, we must realize that this is a societal problem that each of us must address. Sorry I haven't really helped, but it is an important issue and I'm glad you are trying to address it.
(switching over to a different kind of writing, in phrases)
I think kids are more comfortable doing the looking inwards (and outwards)
than adults are.
It may be fairly straightforward to get the children
into a sense of naturalness
of acknowledging differences
while honoring the differences (for the most part--unless the differences are harming others)
at the same time.
You are right. This is a societal problem we must address.
I think kids have to learn prejudices
or instead learn to accept the beauty of a fabric composed of different threads
The kids don't come "preset" (onto this earth) either way, as a given. The younger we can get them, the more this is true.
If we just acknowledge--and to the extent we can, celebrate--differences
we're moving in the right direction.
We also used voicethread to display students opinion of Ethics and Values in Sport. We were not directly tackling racism but rather discussing racism in sport, it was just one topic that was drawn out of the unit.