Find good directories and portals and see who they link to. When in doubt, ask colleagues or pose the question to a discussion list you trust. Busy servers, The Web is a dynamic place. Non-profit sites are going commercial. Sites that offered free services are now charging - and vice versa.
Some popular sites are overloaded and at peak times, it is hard to get in.
Or it is very slow to connect to each new page on the site. Sometimes things aren't working at all. But if you try an hour later, things work just fine. Surfing the web can be a frustrating experience. Initial content on this site developed by Terry Grunwald and David Wilcox of Making the Net Work .