(Please note: this is not necessarily a complete list, but I think these ones are a representative profile of my skills)
Web development: HTML, CSS, Rails, PHP, etc.
Database systems: SQL Server, PostgreSQL, Oracle DB, etc. (including database server administration, performance tuning and query optimization strategies)
High-performance computing: in-depth experience in deployment of large-scale cluster-based calculations on both NUMA and non-NUMA architectures
Miscellaneous: expert in server maintenance (Ubuntu Server, SLES, Debian, etc.) and the use in version control systems (GIT, Subversion)