The Pushpin approach to rendering geocoded data has several advantage over clustering nearby datum into a single composite dot.
Geocoded World Bank projects 
in Asia rendered with one dot per cluster by GeoiQ.
• color and area remain available for coding additional parameters
• spatial distributions with a cluster are preserved to the degree possible
• non-circular clusters result when two clusters are of medium proximity
• individual marks can be added or removed as datasets evolve over time.