I hv been a Flickr member for 5 months, I guess the +/- points are
- fast upload of photos even in bulk
- fast and intuitive user interface especially in organising and tagging of photos
- photos can be easily grouped in sets, and can be sent to interest groups.
- anybody can start a "group" example
100BestB&W, set their own rules, admins , or even make their grp exclusive for invite-only members
- Near limitless "helpful aids" can be installed via Greasemonkey scripts via FireFox browser,
basically enhancing your commenting/sharing/browsing experience. You need to use it to
know how good it is.
- poor customisation ie there is no difference fr your homepage to the others
- still lacking in the hip/arty quotient as compared to deviantart and some other sites.
Guess that is all I can think of.