Why are some words in the posts highlighted as links?

@miajane (359)
United States
November 13, 2006 6:08pm CST
Is it random?
1 response
BellasmamaTiff
@BellasmamaTiff (2544)
• 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....