There is a lot of documentation on how to best engage with Social Media communities. This article is a good start (the blog actually contains loads of advices on how to best handle your Social Media strategy): http://www.britopian.com/2007/05/09/social-media-marketing-rules-of-engagement/

And if you have a little more time you can check this wiki out: http://socialtraining.wetpaint.com/?t=anon. It contains all you have to know about Social Media and how to engage the relationship with bloggers.

I don’t know any existing travel specific Social Media engagement rules unfortunately (It could be the title of a post actually!) but don’t hesitate to contact me again if you have questions!