There are a lot of great shows missing from this list. The Buffy fans are already up in arms. No Dark Shadows?

I assume you're talking about the new top 250 TV. It is based on ratings. No one up and decided which to add. It calculates rankings based on user ratings. If something is not on the list, regular voters have not voted those high enough. With any list, everyone is going to have some they don't agree with...but that's because it's a matter of opinion.

Since the numbers come directly from their "base" they've already done so.

And it's not a written-in-stone list. It'll change based on ratings given by IMDb regular users. This is not meant to be "Beverly's top 250" but it's a list of IMDb regular users' votes. There'd be no reason to ask them to vote again for those they've already rated...that simply makes no sense.

They've had the Top 250 films list for many years and users have frequently asked, "what about one for TV." Now we have it and I am seeing mostly complaints...oh well...

edit to add:

Mr. Ed only has 1,900 ratings and a combined score just above 7. It's rating isn't good enough to be on the list but doesn't qualify anyway since it hasn't been rated enough times (and likely won't get too many more since it aired well before most IMDb users were born).

Same with My Favorite Martian, with less than 1,000 votes.

They need at least 5,000 votes to qualify (and many users are asking that that be set even higher).