I put training videos in a public group in chatter. From the way it's configured right now, I don't have information on how many people viewed the training and how many didn't.

I want to be able to track people who have not viewed training videos and send them reminder emails.

Our Salesforce architect suggested using a visual force page to post to chatter - That would allow us to track who has been clicking on our link. However, one problem I noticed with this approach is that the video link doesn't appear as a nice snapshot in this case, it just appears as a hyperlink which doesn't look very user friendly.

What is the best way of solving this problem? How can we post training videos to public groups in chatter and be able to track and email people who didn't view the training?

Create an Apex trigger for Account that matches Shipping Address Postal Code with Billing Address Postal Code based on a custom field

I used the code below and am getting this error... "Challenge Not yet complete... here's what's wrong: 
Setting 'Match_Billing_Address__c' to true did not update the records as expected." I have no other triggers or validation rules activated. any help would be much appreciated. Thanks in advance

trigger AccountAddressTrigger on Account (before insert,before update) {


List<Account> acclst=new List<Account>();
  for(account a:trigger.new){
    if(a.Match_Billing_Address__c==true && a.BillingPostalCode!=null){
    a.ShippingPostalCode=a.BillingPostalCode;
        
    }

}
}