@madeindex But even without such direct abuses it is bad. For example I tried to block mastodon.social after they started their partnership with Facebook's Threads, but couldn't due to whom I would loose. So there is already a problem.

About your concerns: Contacts and followers will be automigrated (I did it already twice without problems) and you can first check what character and poll limit an instance has (although afaik mastodon.social is *very* unusually low, so this is not really something to worry about, even if you couldn't check it first). And about SEO: At least on DuckDuckGo your website is above your mastodon account, and even if someone where to stumble on your mastodon.social account after migration, they would see where you are now (for example my old account is under https://mastodon.social/@zvavybir and this immediately tells you where I am now).

And yes, Misskey is better…