Linked from
The 14 pages that link to Wilkinson Microwave Anisotropy Probe, each with the reason it gives.
George SmootBroader topic: WMAP refined the anisotropy measurements that COBE had first detected.
CMB cold spotRelated: Its full-sky maps brought the cold spot to broad attention.
Lissajous orbitBroader topic: The spacecraft operated in a Lissajous orbit around Sun–Earth L2.
Dark flowRelated: Its maps supplied key data for early dark-flow analyses.