While the achievement system encourages users to use the Welcome to Gaia forum to complete the Noob Wrangler achievement, please keep in mind that this forum is intended for new members to introduce themselves, and to be welcomed by others. This forum is not to be used to complete achievements.
If you want to make a thread to complete your achievements then you should do so in the Achievement Forum. And to complete the Invisibility achievement you must create the thread in the Chatterbox. Any thread created in the Welcome to Gaia for the sole purpose of completing the achievement are considered spam in this forum, and will be moved to either the Achievement Forum or the Chatterbox.
As for the Noob Wrangler achievement, those quoting new members with out welcoming them will be at risk for being warned for spamming. It is alright to quote new members, but just quoting them or quoting them and stating "just for the achievement" or "you've been wrangled" will be considered spam. Remember that the Welcome to Gaia forum is generally the first forum that new members will post in in which their first experience in the forum should be enjoyable. Quoting them and stating "You've been wrangled" sounds threatening. Lets be warm and inviting to our new members.