Toolstrap was developed to facilitate a unified design across all internal tools. I conceived of Toolstrap in Fall of 2011 and was granted design and development resources several months later.
Although I didn't get as hands-on in the actual product as I may have liked due to other obligations (team-leading a product for Groupon sales teams), I did help sort out the technical architecture and staffing of Toolstrap, as well as guide and product manage it in early stages, and evangelize the technology across the company.
Toolstrap was invaluable for our staff of full-stack developers with limited CSS experience, and helped funnel our less CSS-savvy developers into simply adding appropriate classes and writing particular markup structures, instead of completely reskinning each app as it was produced.
We took a lot of the pain out of developing internal tools at Groupon, and saved potentially hundreds of man-hours of front-end development over the lifetime of the product.