@starfar:
Yes this has been a problem. Apologies for this. The problem should be rectified now, and all the bogus trackbacks have been removed.
A trackback can be thought of as an external WordPress comment, and as a concept is a good idea. If another site using different blogging software links to one of your posts, they can manually send a notification (a trackback) to let you know.
Unfortunately, it’s also a feature that attracts a ton of spammers, and we have been just witnessing this type of (automated) spam attack.
I have also changed the settings for new posts so to prevent the issue from occurring again. This does not in any way affect posting and commenting functionality at iModeler.