I sometimes disclaim (versus trying to always disclose relevant CoI), with a rule-of-thumb along the lines of the expected disvalue of being misconstrued as presenting a corporate view of my org.

This is a mix of likelihood (e.g. I probably wouldn't bother disclaiming an opinion on - say - SCI versus AMF, as a reasonable person is unlikely to think there's going to be an 'FHI view' on global health interventions) and impact (e.g. in those - astronomically rare - cases I write an asperous criticism of something-or-other, even if its pretty obvious I'm not speaking on behalf of my colleagues, I might want to make extra-sure).

I agree it isn't ideal (cf. Twitter, where it seems a lot of people need to expressly disclaim retweets are not endorsements, despite this norm being widely acknowledged and understood). Alas, some 'defensive' writing may be necessary if there are uncharitable or malicious members of ones audience, and on the internet this can be virtually guaranteed.

Also, boilerplate disclaimers don't magically prevent what you say reflecting upon your affiliates. I doubt EA org X, who has some association with Org Y, would be happy with a staffer saying something like, "Figuratively speaking, I hope we burn the awful edifice of Org Y - wrought out of its crooked and rotten timber from which nothing good and straight was ever made - to the ground, extirpate every wheedling tendril of its fell influence in our community, and salt the sewage-suffused earth from whence it came [speaking for myself, not my employer]". I get the impression I bite my tongue less than the typical 'EA org employee': it may be they are wiser, rather than I braver.

I'm in an unusual situation in that I have three different "identities" under which my posts could be categorized: I am an employee of CEA, an EA Forum moderator, and also (in some comments) a private citizen. Since these identities interact in ways that could imply conflict of interest, I try to separate out which one I'm using when it might matter (though not all the time).

I've rarely felt as though a disclaimer was necessary, but I do find them helpful in the aforementioned case of "I work for org X", since that's hard to keep track of otherwise and often lets me know to trust someone's views more than I would otherwise (e.g. if they talk about something related to their org that implies insider knowledge).

I add short disclosure statements when posting about Ought.

I do this because I want to reduce the likelihood of conflict-of-interest stuff coming up. (Feels very unlikely, but could be super messy to deal with if it did happen.)

I've probably been influenced here by GiveWell's early astroturfing controversy (which almost killed the org).

I'm not that much of a fan of adding disclaimers to my posts because it feels cumbersome and assumes that I'd be writing as an employee rather than an individual, when I'd prefer my comments on the forum to be assumed to be the latter. But I tend to include them because my perception has been that people on the forum tend to appreciate precision, and this gives a better sense of what capacity you're writing in, plus I'm not sure I'd be best to judge under what circumstances people would appreciate a disclosure.

Having said that, it has happened to me that something I said informally was quoted in a more formal context and attributed to me as a representative of my organisation, which makes me feel better about commenting off the cuff on things if I can add a disclaimer to try to prevent that.