Issue: Upgrade / import floods all new content lists

We want imported content to be added to the activity list. However, some content that is imported must be converted from another content-type to a wiki type and it doesn't have a defined creation date in the past. This type of content automatically gets today as its creation date, since that is the default value.

I don't know if there's always a good way to avoid this, except maybe if the content has the is_import flag and the creation date is not explicitly set, to exclude that content from feeds altogether. This is not ideal, but would prevent them from burying more important feed content.

Marking as Fixed in the next release.

As of Gamma 6, the following will occur:

• If the content is created automatically by a process (like an import), and no creation date is specified, it will not be added to the stream. Rebuilding the stream later will add this content. This should be considered a desired behavior.
• For the specific case of attachments, there was a bug where the last-upload-date was correctly set during VW3 import, but the creation date was not. The creation date will now be correctly set so that the attachment is added to the correct position in the stream, rather than appearing at the top.