Concept: tech=technology, 4=for, geeks=computer experts and new media enthusiasts. The overall idea is : Technology for computer experts and new media enthusiasts.
From my point of view I believe that domain names that use numbers as words could be stand from the crowd when used clever and creative.
Uses: Could be used at technology, Computer & Networking, Internet & Web, start ups, websites, blogs, forums, communities etc.
Niche: The tech keyword has low competition and global monthly searches 55,600,000! according to Google keyword tool
Cost of advertising: Approximate CPC 1.12 euro (Google ad words)