How can legitimate senders get caught in spam filters?

Poor list practices trigger filters: purchased lists containing spam traps, unconfirmed signups including invalid addresses, and stale lists with abandoned accounts. List quality problems resemble spammer behavior.

Content triggers include: spammy phrases ("Free!" "Limited time!"), excessive links, image-heavy layouts, and missing unsubscribe links. Legitimate marketing sometimes uses language similar to spam.

Reputation damage from past issues persists. Previous problems, shared IP reputation, or domain history can affect current sending. Understanding why you're filtered helps address root causes rather than symptoms.