The Don't migrate crap rule is covered extensively in the comments on EEAA's answer, but I thought it should be explained more clearly:

"Don't migrate crap" is excellent summary of the attitude towards migration across all SE sites and it's a very useful single rule, but it's not the only rule.

Look at Gilles's comment on Jeff's official answer; there's another rule there: don't bother migrating if there are already a ton of dups on the target site.

As I mention in this answer, in all the discussion on meta.SE about migrations, there's another rule: the default action should be to close questions in place (not migrate them), only questions that are clearly good and on-topic should be migrated.

We had extensive discussions here when we got SE staff to remove SF as a target for SO migrations and another rule came up: If you're not active on the target site, you probably aren't qualified to judge if something is good and on-topic, so it's reasonable to simply close it in place.

Another thing that came out of our discussions here about being a migration target is that unless the person asking is active on the target site, it's usually better not to migrate - the OP rarely follows a migrated question.

So that's 5 rules w/out looking very hard:

1. Don't migrate crap
2. Don't migrate if there are multiple dups on the target site
3. Only questions that are clearly good and on-topic should be migrated
4. If you aren't active on the target site, you can't really judge if something is good and on-topic
5. If the person asking isn't active on the target site, it's not worth migrating since the question will likely be abandoned

As I said, "Don't migrate crap" is the overal attitude towards migration, but these other rules make it clear why there's no need to make migration easier: it's far more common for a migration to be inappropriate, so it should be avoided as much as possible.

The Don't migrate crap rule is covered extensively in the comments on EEAA's answer, but I thought it should be explained more clearly:

"Don't migrate crap" is excellent summary of the attitude towards migration across all SE sites and it's a very useful single rule, but it's not the only rule.

Look at Gilles's comment on Jeff's official answer; there's another rule there: don't bother migrating if there are already a ton of dups on the target site.

As I mention in this answer, in all the discussion on meta.SE about migrations, there's another rule: the default action should be to close questions in place (not migrate them), only questions that are clearly good and on-topic should be migrated.

We had extensive discussions here when we got SE staff to remove SF as a target for SO migrations and another rule came up: If you're not active on the target site, you probably aren't qualified to judge if something is good and on-topic, so it's reasonable to simply close it in place.

Another thing that came out of our discussions here about being a migration target is that unless the person asking is active on the target site, it's usually better not to migrate - the OP rarely follows a migrated question.

So that's 5 rules w/out looking very hard:

1. Don't migrate crap
2. Don't migrate if there are multiple dups on the target site
3. Only questions that are clearly good and on-topic should be migrated
4. If you aren't active on the target site, you can't really judge if something is good and on-topic
5. If the person asking isn't active on the target site, it's not worth migrating since the question will likely be abandoned

As I said, "Don't migrate crap" is the overal attitude towards migration, but these other rules make it clear why there's no need to make migration easier: it's far more common for a migration to be inappropriate, so it should be avoided as much as possible.