Create a comprehensive account-based marketing (ABM) strategy for our <B2B product/service>, focusing on developing personalized regional microsites and integrated direct mail campaigns. Start by proposing how to define the top 50 target accounts across <X> key regions. For each region, design a customized microsite template that can be easily personalized with account-specific content, case studies, and tailored value propositions. Develop a content strategy for these microsites, including interactive elements, personalized calculators, and gated premium content. Then, create concepts for a series of high-impact direct mail pieces that drive traffic to the microsites, such as dimensional mailers, personalized videos, or executive gifts. Outline an integrated nurture strategy that combines the microsite, direct mail, email, and sales outreach touchpoints. Finally, provide a framework for measuring the ROI of this ABM program, including metrics for engagement, pipeline influence, and closed-won business.