I want to offer email marketing but analyze: is email marketing still effective enough to sell as service? Map email marketing: open rates declining, spam filters, competition. Calculate: if I charge $500/month for email marketing, what results must I deliver? Show me the email marketing viability: still works for these businesses, doesn't work for these. Give me the email strategy: sell to these clients, promise these results. Include: whether email marketing is still valuable, what niches need it most, and what results are realistic.