As Yoric says (btw, Yoric: check your DMs ;P), #1 and #4 sound like a good case for maintaining different personae. For #2, i guess you'd need to petition whoe

As Yoric says (btw, Yoric: check your DMs ;P), #1 and #4 sound like a good case for maintaining different personae. For #2, i guess you'd need to petition whoever maintains the blocklists who were blocking you. Or give up and start a new identity. For #3, Yeah, there's a risk here that somebody enthusiastically starts building a reputation list for The Best Marxist Content and puts the hash of your user ID on it. Someone then reverses the hash via dictionary lookup or similar and proves that you were on the list, and promptly tries to arrest you. Frankly that risk exists already today, though. We may need to try to think of better pseudonymisation approaches than just hashing though.