Persistent surveillance is an intricate process requiring monitoring, gathering, processing, tracking, and
characterization of many spatiotemporal events occurring concurrently. Data associated with events can be
readily attained by networking of hard (physical) sensors. Sensors may have homogeneous or
heterogeneous (hybrid) sensing modalities with different communication bandwidth requirements.
Complimentary to hard sensors are human observers or "soft sensors" that can report occurrences of
evolving events via different communication devices (e.g., texting, cell phones, emails, instant messaging,
etc.) to the command control center. However, networking of human observers in ad-hoc way is rather a
difficult task. In this paper, we present a Twitter web-service for soft agent reporting in persistent
surveillance systems (called Web-STARS). The objective of this web-service is to aggregate multi-source
human observations in hybrid sensor networks rapidly. With availability of Twitter social network, such a
human networking concept can not only be realized for large scale persistent surveillance systems (PSS), but
also, it can be employed with proper interfaces to expedite rapid events reporting by human observers. The
proposed technique is particularly suitable for large-scale persistent surveillance systems with distributed soft
and hard sensor networks. The efficiency and effectiveness of the proposed technique is measured
experimentally by conducting several simulated persistent surveillance scenarios. It is demonstrated that by
fusion of information from hard and soft agents improves understanding of common operating picture and enhances situational awareness.