Account based copy fails when it is segment copy with a company name pasted in. The brief is meant to be the source of every sentence, not a warm-up exercise before writing.
Multi-threading is not sending the same email to more people
Buying groups talk. Two people in the same department receiving near-identical outreach in the same week is the fastest way to be dismissed as automated, and it happens constantly because multi-threading gets implemented as a contact count rather than as a strategy.
Each contact gets an angle that fits their remit and a thread that makes sense alongside the others. If the group compares notes, which they do, the picture should look like a company that understands the account rather than a tool that found four addresses.
Citing the brief
Every touch is tied back to a specific point the research established. This is a constraint on the writing, and it is the constraint that makes the output different from ordinary personalisation. If a sentence cannot be traced to the brief, it is a general claim in an account specific email, and the reader can tell.
Entry strategy is separate from cadence
Where you enter the account is a strategy decision: the practitioner who feels the pain, or the executive who owns the budget, and how the introduction passes between them. The sequence cadence is just timing. Conflating the two produces a thread map that is really a send schedule.
Runs well with
Skills compound. These are the ones we usually install alongside it.