Therefore, use a LegalSolution: make use of your DefensiveCopyright. Everything you write is copyrighted by default, so provided that you don't contribute to places that require you to implicitly or explicitly dilute your copyright, then you have a defensive copyright already, and it only remains for you to decide whether to use it.
That said, there are measures you can take to make it stronger, and intimidate people who AvoidLegalRisk. Legally such measures make little difference, but appearances can be important too, in a social context. For example:
While this might seem to be a misuse of copyright, which we normally think of as protecting commercial interests, copyright was written in part for such things as private journals: hence the BerneConvention stipulation that content is copyrighted by default.
But, this doesn't work for famous people. When famous people find that their letters have been made public by the recipient, or their phone conversations recorded, they can rarely use copyright law to protect it, but have more success with privacy laws. In any case, DefensiveCopyright doesn't protect you against small excerpts, conversations rewritten as summarised reports on those conversations, and similar workarounds.
For ordinary people, laws like the OCILLA part of the DMCA provide an avenue for the use of defensive copright, since a hosting company is likely to act on the takedown notice even if its local law does not require it to. Even where the hosting company chooses to ignore the notice, there is harassment potential from an OCILLA identification subpoena and the requirement that the host has a policy of terminating repeat offenders, so a subsequent incident may achieve the desired result. This is largely ineffective against wealthy targets, for those will tend to have readily available resources to host their content in locations immune from action, such as their own server. In such cases, serving notices on search engines becomes the tool of choice, causing the content to become too obscure to be found even though it is still present.
Alternatives: DefendAgainstParanoia. It might not be necessary.
To-do: reduce cynicism, increase charity.
Sensitive text like OnlineDiary, random FlameWars, our random banter, FrontLawns, MessageBoxes, and other LifeInText should not automagically get distributed in places where they may be read out of context. (cf. CommonContext, ContextSwizzling). Sometimes the exact wording is sensitive, and we don't want people to mess that up. OpenContent removes the choice of republishing from the author, in favour of the world.
The author has already lost that choice by publishing. InformationWantsToBeFree. Copyright can't protect you. FairUse is powerful enough to allow quoting out of context without coming close to violating copyright.
Just because something is possible doesn't mean it is automatic. I can murder you, doesn't mean I will. I can also steal, but that doesn't mean I will. Discipline, punishment, and guilt are important factors in life. We aren't all sociopaths incapable of understanding social rules and mores. Besides, you don't have to allow more than FairUse, like say taking an entire FlameWar and archiving it. That's still illegal, although in actual reality, those are the most frequent copyright violations.
Punishment is important, but prosecutions under CopyrightLaw are not a tool that I can effectively wield to inflict punishment. It is better to rely on social mores for protection. By placing my words into the public domain I hope to generate good will. Then people will be less likely to want to attack me, and more likely to defend me if I am attacked. This is a better defence than relying on copyright laws.
The effective point of the copyright notice in defensive circumstances is to have something to twist CryptoNauts with, as they are so legalistic that some will only respond to a copyright notice, even if they have no idea what a copyright actually is. That isn't a LegalThreat, but mind manipulation (well, actually, a shortcut negotiation). In more positive circumstances, it is a GuidePost - the written description of the community's values. This makes it a good way for newcomers to your community or other third parties to evaluate what relationship they want to have with your community (as LifeInText). Copyright for OnlineCommunities is chiefly moralistic (cf. CommunityExpectation), not legal - punishment is not necessary.