When looking into this, I quickly found traces of the Virtual Reference Desk Project, associated with "AskA" services. This was an ERIC-related project which spun off several projects and services. The VRD and AskA were asynchronous web question and email based services, and were not using synchronous instant messaging methods.

The Virtual Reference Desk Conference ran for several years, and as The Librarian in Black notes, became the Reference Renaissance Conference which takes place every two years. Unfortunately, many links to the older VRD pages are broken and unavailable for future reference.

The successor to the Library of Congress' Collaborative Digital Reference Service (CDRS), OCLC's QuestionPoint is a chat tool for reference librarians. To the public, this appears as a web page with a chat frame on the left and a frame on the right where the librarian can display other web pages.

Sometimes chat is not easy to find. The Library of Congress "Ask a Librarian" web page has a chat symbol for some topics, and clicking on the symbol goes to a question submission page with a Chat-Available box on the side. Clicking on the chat box during the hours when a librarian is available brings up an introductory page where you type your question (and where their chat tips are offered). Submitting the question takes you into a QuestionPoint chat page.

Some organizations have ended use of chat tools for several reasons, although most are willing to restart it.

As the long list of libraries which are using online tools shows, there is continuing interest in several kinds of online services. Use, experimentation, and research is continuing.