If you remember a week or two back, someone set up a server to provide full text searches for Mastodon, but soon took it down after getting feedback that it was rude to provide this service (https://fedsearch.io/). However, I think he was doing us a great service by showing us what is technically possible. That specific server may have come down, but his sense of propriety will not stop others from setting up their own, private versions of the servers. With the current growth of Mastodon, we can be sure that similar search servers will be created by many parties for their own use -- law enforcement, copyright enforcement, background checks, journalism, advertising, etc. For the time being, it may be beyond the capabilities of the random Internet troll or fascist club (as long as they don't have support from more powerful terrorists), but before long the capability to set up a search engine will probably be in the hands of your average script kiddie. While these capabilities develop, your average Mastodon user will blithely use the service as though general search capabilities do not exist, exposing themselves to unnecessary risk. What's more, if any newsworthy content appears on the Mastodon network, all of the above people will have access to that information before the rest of us do. This doesn't sound like a good arrangement to me.