I personally feel that the majority of our members here are really good about not assuming when reading posts, questioning when it's not clear, etc. There are times that assumptions can be made in emotional threads, etc. However, I think the whole is really good at not making assumptions...unless there's a history or high emotion somewhere in place.
I do think there are other acts that can come into play when communicating online and those
appearance and
interpretation.
Many times upset can happen because one is upset that their words are misinterpretted or they've misinterpretted the words of another. However, alot of those times that can happen due to appearance, then interpretation/understanding, upon reading.
Regardless, it's all boils down to communicating our words in the best way that we can for understanding in our presentation. For example, I could say, "Dangit, I'm so ticked!" and everyone here could wonder what's up, am I upset with them, searching their minds for past conversations to see if I was alluding to them, etc. When
none of that would happen if I would've said from the beginning, "Dangit, my hubby said such and such and I'm in a bad mood and I need to feel better." Using complete sentences which completes our thoughts help us not to be misunderstood, leaving others to wonder, interpret the best they can, and assume our meaning...because of the appearance of our statements.
In my above example, if someone were concerned that I was alluding to someone here, or to them, would they be assuming or would the appearance of my words have allowed for an interpretation other than what I meant? If someone misinterpretted due to the appearance of my words, I will just clarify as I've had to do MANY times over the years.
We have appearance here through our words, and a few emoticons/smilies, but that's it! Others can't see our smiling faces, our tears rolling, our hearts breaking or dancing, the wink when we're being sarcastically humorous. Words are what we have here. Using them fully and completely can be paramount in making points and being understood.
On the flip side of this, if we think we're not understanding completely, we need to ask a member to expand on their thoughts for a better understanding and there's not as much left to try to inprepret, leaving less room for misunderstanding.
Also, when we post publicly, we need to be willing to accept all responses to the thread...even those that disagree with us. That's what conversation is about, I feel. As long as someone disagrees respectfully (even when angry and it shows), that's OK! I might end up saying, "We'll agree to disagree here"...showing that I respect their argument but am holding fast to my belief as well.
Bottom line, I think it has more to do with appearance and acceptance than it does about assumptions...even though assumptions can and do happen.
In a forum this size, we're going to have those agree 100% percent, those who don't respond because they have no opinion one way or the other, and those who disagree completely. As long as it's respectful, it's all OK. That's what make a conversation...especially a conversation with many.

It's all part of sharing and giving/receiving support...in its many forms.
KD