Why are some words in the posts highlighted as links?

@miajane (361)
United States
November 13, 2006 6:08pm CST
Is it random?
2 responses
@borg_queen (2535)
• Philippines
14 Nov 06
Adverts.
• United States
14 Nov 06
I think the highlighted words are words that have been used as tags in other discussions. Im not 100% sure though....