A few days ago i added a new option to the user profiles in a vbulletin forum ( http://www.seo-romania.com/forum ). This option let the users have on their postbit a link to their http://linkedin.com profile.

See the link to the linkedin profile below the user info in the following image or go directly to the forums http://www.seo-romania.com/forum/showthread.php?t=304 .

It's simple to achieve this, just follow the next steps:

1. Go to admincp -> User Profile Fields -> Add New User Profile Field
Select a "Single-Line Text Box" from the dropdown menu, press continue and in the next page just enter something on the "Title" field.
Save. After you are done with this, write somewhere the field id (field6 in my case)

Mine looks something like this.

and on the user profile page looks like this (i've added a "how to use" for users):

2. Go to this link http://www.linkedin.com/profile?promoteProfile=&trk=mypro_badges (you must be logged in tho see the page), select a button you like and copy the code from the right side.

Go back to you vbulletin admin panel -> Styles & Templates -> Styles & Templates and select "Edit Templates" on the theme you like to have this feature on. From the style templates list, double click on "Postbit Templates".