I currently only see belongs on meta.cs close reason, when you choose to close as off-topic. Is it possible to add stackoverflow to it?
Migration paths are normally not created from or to beta sites (there can be exceptions if we demonstrate an evident need). You can always flag to request a migration.
In the last 90 days, we only migrated 13 questions away to SO. 2 of these were rejected (i.e. subsequently closed on the target site), 1 rightly (in my opinion as an SO user), 1 because the asker deleted his own question. So we have a good success rate for migrations (I do sometimes filter by closing as straight off-topic questions that were flagged for migration but I think will get shot down as low quality on SO).
On the other hand, barely more than 1 question per week is not enough to create a migration path. When the figure gets to 1 per day, maybe. For the time being, keep flagging.
Do note that sometimes people ask very low-quality programming questions (e.g. a code dump and no more information than “it doesnt work”). We don't want to migrate these. Sometimes they ask on CS or other vaguely programming-related sites because they've been blocked on SO for posting too many low-quality questions — in those cases, even if we do migrate, the migration is automatically rejected (it shows in the question history as closed, locked, unlocked in quick succession).
Migration is mod-only on beta sites since Oversight has decided that beta sites should not migrate away, but close on site in order to shape the profile of the site in a visible way.
We have been migrating some questions because
- because we think we know our scope well enough and
- because of the amount of clear mispostings of SO-questions.