If your snippets are Ruby snippets, I'd suggest boson. I use it to maintain my repository of 450+ ruby commands (snippets). I search my commands by name, description, usage, alias and other fields as well as sort by them.
Since my commands reside in local files, I can easily export to gists or install gists as boson commands. I can do all of the things you want to do except list by date and tag. Listing by date is trivial (timestamp of the file) and tags is something I'd like to add to boson as a plugin one day.
