How to activate trackback?

They just ‘happen’ – when someone trackbacks to you, it will appear in the comments.
Do you mean something like ‘Trackbacks (0)’ ? If so, that must be done using a hack / plugin. It’s not built into wp.

Go to your Admin Panel > Options > Discussion > Discussion Options and check the box by “Allow link notifications from other Weblogs (pingbacks and trackbacks.)”

Do you mean something like ‘Trackbacks (0)’
Yes I’m searching for a way to display it like this. Can you recommend a plugin or hack? I checked last week may plugins & hacks but can’t recall any, which offers this function.

Out of curiousity, why do you want to show that you have no trackbacks?

Out of curiousity, why do you want to show that you have no trackbacks?
I think it is an good idea, to have almost the same appearance of elements. So the user knows “ok tracksbacks are place next to the comments link, let’s see ..”. The user doesn’t have to wonder why this link appears sometimes and sometimes not.
The way I would like to implement trackbacks, is the same way as comments are displayed by default in WordPress.

I wanted to show that trackbacks are welcomed and the easiest way to do it just seemed to be to continue using the WP system that automatically shows trackbacks along with the comments, but edit my main template re: comment display to include “or Trackback” like this:

<?php comments_popup_link(‘Leave a comment »’, ‘1 Comment or Trackback »’, ‘% Comments »’); ?>

Not the same as breaking down Comments | Trackbacks but good enough for my purposes. Hope this helps.