How to blur a reply to a topic and ask guest to register or subsricibe? Picture

[mggevo]

Greetings,
This is my first post and hope this is the right place for this.
I have been trying to see if there is such mod or custom cod to this as, I have seen this in many forum sites.
When you get your topic replied the next or best answers comes in a blurred vision with a note on the top asking guest to register or subsribe!
Below is the picture that is done in SMF forum and still don't know how this can be done.!
Thanks

[Kindred]

ick blah... yuck...

I can not recommend doing that -- that sort of behavior actually chases AWAY users rather than encourages them to participate.

[mggevo]

Thank you very much but, still need to know how this can be done though!

[Kindred]

looks like a custom mod, since I have not seen anything like that on our mod site here...   why don't you ask the owner of that forum?

[mggevo]

ok thank you!

[Bigguy]

I don't like seeing that on sites I visit either. It's just a real turn off. Nothing worse than searching for something...finding the answer and then having something like that pop up. I have to agree with Kindred on this.