Region rating
== PG in Second Life ==
Let's see what is the Second Life Terms Of Service says about PG: ... ... ...um... nothing.
Let's jump to the Privacy Policy: ... ... ...still nothing...
Community standards: Oh! Surprise! there is something:
5. Indecency Second Life is an adult community, but Mature material is not necessarily appropriate in all areas (see Global Standards below). Content, communication, or behavior which involves intense language or expletives, nudity or sexual content, the depiction of sex or violence, or anything else broadly offensive must be contained within private land in areas rated Mature (M). Names of Residents, objects, places and groups are broadly viewable in Second Life directories and on the Second Life website, and must adhere to PG guidelines.
Policies and Policing
Global Standards, Local Ratings All areas of Second Life, including the www.secondlife.com website and the Second Life Forums, adhere to the same Community Standards. Locations within Second Life are noted as Safe or Unsafe and rated Mature (M) or non-Mature (PG), and behavior must conform to the local ratings. Any unrated area of Second Life or the Second Life website should be considered non-Mature (PG).
So, that means you can chit-chat about the weather, sleep, or build something in PG areas, but nothing "offensive" that a 18 year old must not see (minors aren't permitted to visit the main grid, remember? TOS 2.2).
If you are curious what are those "PG guidelines" mentioned above, you'll run into the section that's refers to itself.