Q: Add a pop up box for each user/IP to see just 1 time I don't know exactly what to search for when looking for info on this so here we go...
I've recently made a change to my MVC website (all the code parts are VB, not like most examples which tend to be in C#).
Once a user logs in, is there a way to show that user a pop up box, or a div, which simply explains the changes made (the text in the box is not important).
I only want the user to see this ONCE! 
Example:
As soon as the user goes to the URL, they get a pop up box saying "You now have to add your name when creating a new post"
But of course, the user doesn't want to see this EVERY time they log on to the page.
Any pointers would be lovely,
Cheers.

A: You would need to in some way track that users have seen the message.  If there's any likelihood that there will be future such messages, maybe any value in tracking when users saw the message, etc. then this can all be put into a fairly simple database structure.
Maybe a lookup table of messages:
ID | Message
-------------
1  | "This is the text of the message, or maybe the whole HTML, or some other data, it's up to you."
2  | "Other message, etc."

And a table to link that to users:
UserID | MessageID | DisplayedOn
--------------------------------
123    | 1         | 2014-01-30 08:56:21

You can even make the messages more "interactive" and have an "Accept" or "I Understand" button, requiring that the user accept the message or see it again until they do.  For something like that you can change DisplayedOn to FirstDisplayedOn (maybe include a LastDisplayedOn?) and also an AcceptedOn to track that interaction.  This could be very useful for updates to terms of service, for example.
Then when a user logs in, when you fetch the overall user context/object from the database you would include any messages they need to see, haven't seen yet, haven't accepted yet, etc.  Your UI can then display whatever it needs to display based on that.

A: As you want to show popup only after user has logged you need to store information about who has seen this popup. I am guessing that you already have database and data access layer all set up. So, you need to add a new table with following columns:
Id | UserId | PopupId | ShownOn

Before displaying popup you need to query this table to see if user has already seen it. If not, just show the popup and insert a new record in data table.
As we don't know how you access your data it is impossible to give more precise solution.
