I spent the last two years building compilers and relational databases at Eve (http://witheve.com/).
Before that I spent several years consulting. Some highlights:
Item-item article recommendations for Springer users based on ~600m past downloads. Uses locality-sensitive hashing and external sorting to run on a single low-powered server. https://github.com/jamii/springer-recommendations
Built a prototype replacement for the core trading engine at the Smarkets betting exchange: 10x less code, 40x better throughput, 10x better 99% latency.
Built a LaTeX aware search engine to power latexsearch.com. Covers the entire Springer library – more than 8m LaTeX equations. Searches by tree-edit distance on compressed syntax trees, using suffix arrays as a first-pass filter. https://github.com/jamii/texsearch
Parallelized a constrain-logic programming DSL - http://scattered-thoughts.net/blog/2012/12/19/search-trees-a...
jamie@scattered-thoughts.net - http://scattered-thoughts.net/resume/ - https://github.com/jamii/