Oke, but... only within the hour or something like that. After that the removal time of the posts gets expired. Reason: Otherwise you could create chaos: ppl refering to unexisting posts, quoting unexisting posts,...
So, edit, removal: oke, but within restrictions: within the hour or before the next post or quotation in the same topic.
In the beginning of this lesson, where we learn about ICT technologies, I once posted something "off topic" and afterwards I wanted to remove it because I thought it was maybe inappropriate, but it wasn't possible... I really think students should be allowed to remove or edit their own blog posts.
What afierens suggests, is reasonable: referring or guoting unexisting posts is a probable flaw of the free system. But it can also seem necessary to delete or modify a blog post after one hour. Maybe there should be a button provided, who allows you to send in one click a notification to the administrator, saying you want to delete/modify your message. With another tool he can check easily if the blog post is quoted or not: if not he can delete it immediately. Now students have to post a message in the forum just to ask the administrator to move a message. That's very unefficiƫnt.