Currently, when you add a comment on an idea from Aha!, the default is to post it publicly on the portal. I have had a couple of instances now where someone accidentally publicly posted a comment that should have been private. It would be great if the default was internal (or changeable to be internal) so we don't accidentally air info that isn't intended for public consumption.
In my company's setup, we aren't utilizing a public ideas portal at all -- defaulting to a "public comment" is a bit confusing (and one extra click for everyone on our team)
We can see that there can be potential situations of accidentally posting comments which should have been private. Upon posting a comment in Aha!, there is the option to delete the comment so that it no longer appears in the Idea itself. This can be a way to correct any errors made which were not meant for public consumption.
We've also heard feedback from the community that they tend to focus on the public comments more so than the private comments, which was one of the reasons behind the original design.
At this time, we are unlikely to implement this feature, but hope that the "delete" functionality can help with any accidental errors. I hope you can understand.