This past Tuesday, I had the chance to sub for a shift on our statewide chat reference service. This was my first "live" experience of providing virtual reference. It went quite well.
I manned the computer from 6-8, sitting in my office (a mostly-transparent cubicle adjacent to the reference desk) while our student worker manned the reference desk. She sent reference questions on to me, but this allowed me to pay the most attention to any incoming chats, and to explain to students who came in that I might have to shift gears at a moment's notice.
I had 3 chat questions over the two hour period, which was good for a first shift (not trying to balance several questions at once, for example). They were all fairly simple to answer; the most nerve-wracking part was accessing the patron's home library information (each patron that signs in comes from a particular library's portal--the librarian staffing the service can get information about that library, including how to access the catalog, how to get the patron access to databases, etc.). It went very smoothly, but I was nervous about messing that part up. All 3 patrons were community college students, so their questions were similar to the questions my regular students have (I need articles/books to do a paper on x, I need to cite x source in MLA/APA style).
I was also happy not to have any "emergency" questions. On a fairly regular basis, (public) librarians will get medical or legal questions, to which we can offer sources or referrals, but not advice. Every now and then, one of these questions will be more urgent--I brushed up on some state emergency referral services/hotlines just in case, and was happy not to have to use them!
Overall, it was a good experience, that I hope will help pave the way for offering our own virtual reference. One challenge will really be staffing levels--when there aren't any incoming chat questions, I can help in-person patrons just fine, but once the computer dings, I have to give it all my attention. This means we may often need "double coverage" for the chat reference and the reference desk--maybe a good chance to pull in library students?