Now you've done it. You've barely been on the board five minutes and you've triggered the Single-Issue Wonk, or the resident Hair-Trigger Temper has singled you out for punishment. You didn't mean any harm, but everyone on the board is determined to make you out to be a Troll of the worst order, twisting your own words in order to make you the message board's resident criminal. Even the Butt-Monkey of the board is sneering at you loftily. Better jump ship before you're made to walk the plank...
Except... Wait. Someone's taken your side. About two thirds down a long list of "stupid n00b" posts is one that reads "Actually (s)he has a point," or "Lay off. How was (s)he to know that episode 45 is a taboo topic?" And the thing is, the other members of the forum actually listen, posting sheepish apologies or half-hearted grumblings before seeming to forget the whole incident entirely. Come to think of it, your champion is the same person who was the first to respond to your "Hi, I'm new," post, with a "Welcome to the board!" and a list of useful links.
Lucky you. Your new forum has a Shepherd in residence.
The Shepherd is a rare and benevolent online persona. They make it their mission to greet the newbies, ensure everyone treats them fairly, and answer the questions that die hard fans find too inane to be worth answering. Usually a member held in high esteem, they're well liked by nearly everyone, even the one who Suffers Newbies Poorly, which is why your attackers shut up the minute The Shepherd entered the fray.
While the actual personality can vary from an affable "big brother" type to someone who's downright motherly, the definition of the Shepherd is someone who looks after the Newbies that might otherwise have a hard time being accepted. They're no pushover though — often, in their role of Defender of the Newcomer, they will challenge Mods or other "Old Guard" members determined to assume the worst. And they'll win, some times... Baiting or annoying this character is an automatic Kick the Dog. They genuinely have no ulterior motives (if they do, they're something other than The Shepherd), so other members of the forum will rally to their defense, especially if they were once Newbies who were welcomed by the Shepherd.
So you got lucky. The forum's given you the benefit of the doubt, and the slate is wiped clean. Don't abuse your benefactor's trust though... if you turn out to be a Troll, the Shepherd will hammer you twice as hard for betraying their trust.
Some especially rabid newbie haters will accuse the Shepherd of white knighting, but if the Shepherd is good enough typically these people will be scolded and admonished for attempting to tarnish the Shepherd's reputation, though it is indeed true that at some base level The Shepherd and the White Knight have very similar motives. In many cases can be a Good Shepherd.
Has nothing to do with any other character named Shepherd or some variation thereof. Or literal farmers who tend for sheep.