Updated documentation.

doc/snac.1

@@ -269,7 +269,7 @@ for a job to be assigned), input or output (processing I/O packets)
 or stopped (not running, only to be seen while starting or stopping
 the server).
 .El
-.Ss Migrating an account from Mastodon
+.Ss Migrating an account to/from Mastodon
 See 
 .Xr snac 8
 for details.

doc/snac.8

@@ -381,7 +381,81 @@ is supported. Intentionally, the
 and
 .Pa /following
 paths return empty lists.
-.Ss Migrating from Mastodon
+.Ss Migrating from snac to Mastodon
+Since version 2.60, you can migrate your
+.Nm
+account to other ActivityPub instances. I will describe the process to do it from
+.Nm
+to Mastodon; on other software implementations, it will surely be very different. All
+the steps regarding your
+.Nm
+account must be done from the command line. For the sake of the example, let's
+say that you want to migrate from an account named @origin@snac.example.org to
+another one named @destination@mastodon.example.com and that both of them
+already exist. I've used this very informative page as a guideline:
+.Pp
+.Lk https://fedi.tips/transferring-your-mastodon-account-to-another-server/
+.Pp
+1. On your
+.Nm
+server, first export your data to CSV by running:
+.Bd -literal -offset indent
+snac export_csv $SNAC_BASEDIR origin
+.Ed
+.Pp
+You'll find the following CSV files in the current directory:
+.Pa bookmarks.csv ,
+.Pa blocked_accounts.csv ,
+.Pa lists.csv , and
+.Pa following_accounts.csv .
+.Pp
+2. In the web interface of your new Mastodon account, click on
+.Vt Preferences
+>
+.Vt Import and Export
+>
+.Vt Import
+and upload the CSV files one at a time. You must specify the type of
+file you are uploading.
+.Pp
+3. Still in the web interface of your new Mastodon account, click on
+.Vt Preferences
+>
+.Vt Account
+>
+.Vt Moving From a Different Account ,
+then click on
+.Vt Create an account alias
+and follow the instructions. (When it asks you to
+write your old account’s handle, it needs to include the @ at the start
+as well as the @ in the middle, in our example, @origin@snac.example.org).
+According to the link above, you must wait at least five minutes for
+this to be effective.
+.Pp
+4. Meanwhile, you must tell
+.Nm
+about your new account by creating an alias from your current one.
+So, on your
+.Nm
+server, run
+.Bd -literal -offset indent
+snac alias $SNAC_BASEDIR origin "@destination@mastodon.example.com"
+.Ed
+.Pp
+5. Finally, you must order
+.Nm
+to start the migration process, that will consist in iterating all the
+people that follows your account and sending them a
+.Vt Move
+message, notifying all of them that they must unfollow your old account
+and follow the new one. The command is
+.Bd -literal -offset indent
+snac migrate $SNAC_BASEDIR origin
+.Ed
+.Pp
+This process can be very long and unreliable. I recommend you to read
+the document I linked above to know how heartbreaking it can be.
+.Ss Migrating from Mastodon to snac
 User migration from different Fediverse instances is a pain in the ass
 that has been implemented everywhere as a kludgy afterthought. There is
 not much that can be done, other than importing the list of people you