In developing a library's own 23 things, I think the most important issue is customer input.
Kids, for example, are way at the forefront of the learning curve for computers. If some new site or portal or web service becomes popular, odds are that they'll be the first to hear about it.
Second, the next source of input would be from "niche" groups. These are specific groups that use the web technology to flourish. Notable points are groups that use blogs, Facebook, Ning, etc. to facilitate meetings and to get new members. Another adaptation is that food trucks (The kind that sell take-away lunches) are using Twitter to let people know we they are at a moment to moment basis.
Finally, and specifically for library staff, there are online books and databases. This is a way to access huge amounts of info on just about any subject at virtually no price. This is a hugely useful resource.