We have mods now, that can change a lot of things, among them the site-description in the tour.
It currently reads:
Open Source Stack Exchange is a question and answer site for people organizing, marketing or licensing open source development projects. It's built and run by you as part of the Stack Exchange network of Q&A sites. With your help, we're working together to build a library of detailed answers to every question about open source software.
It is outdated, as it still talks about open source software, although we already moved on and expanded the focus of the site. Read here about our focus as it is defined currently.
So, what should the current site-description contain? Please provide the full text maybe with some explanation. Vote on the suggestions you like.
There was an older meta-discussion about the site-description, but it only asked about inclusion of free software and was still software-focused.
EDIT: You can (and should) use $SiteName (as in the answer of ArtOfCode), as this is autmatically replaced with the current site name.