Look like there are hundreds of meta users at exactly 101 reputation. Why is that? And how much is one up vote worth? Easy Q's.
New accounts start with one rep.
Account association for users with over 200 rep on one site gives a 100 point bonus to their account on the new site. That is how you get the 101 rep.
Each upvote is worth 10 points for answers and 5 points for questions as long as your answer or question is not community wiki and you are not over your daily rep limit already.
In the case of meta everybody's SO profile was copied over (which is why a lot of people have the same user id on SO and Meta) to create the initial population of users. Most of these won't have been interested in using meta so they'll have the initial amount of rep which I believe was set to 101 to enable everyone to vote down straight away (NOTE this was before the reputation required to vote down was increased to 125). This was later formalised as the 100 point bonus for linking accounts.
New people registering will start at 1 unless they link a 200+ point account from SO, SF or SU.