Yes, four waitlists at a time, no other limit. Find a better option you want to waitlist? Cancel one of the four and enter the new waitlist. There is currently no way to check active waitlist requests other than calling in, so I maintain a super simple spreadsheet with the date the waitlist is entered and the timeframe and unit type(s) waitlisted. Much easier than calling in from time to time.
Waitlist dates may be duplicated. Statistically, it is easier to match a waitlist for 3 or 4 dates than all 7 at once, so I enter one waitlist for all 7 (a couple times I got lucky), and one waitlist for the first 3 dates and one waitlist for the second 4 nights. Most of the time I am looking for Sun. or Mon. through Thursday, so one waitlist for all 4 or 5 nights, then two waitlists for the split.
When entering a waitlist by phone, a likelihood of success from 1-3 is quoted. 1 "Likely", 2 "50-50" chance, 3 "Possible" but have an alternate reserved. Owners may cancel an existing reservation to reacquire credits to book the waitlist match. Only a couple of times have I been at a "2" level instead of "1", but I enter waitlists as soon as possible for the tough to book resorts.
There is currently no waitlist request confirmation -- only waitlist matches by email or phone, which is set up when the request is placed. Waitlist requests are entered manually, so errors get made. I usually call a couple of days after a request to confirm the waitlist request was entered correctly. There are some reports of waitlist requests "dropping"; I make a fair number of waitlist requests and have never experienced this.
My waitlist success rate must be better than 90%. Part of this is due to the fact that about 30% of WorldMark reservations are cancelled at some point. Quite a few waitlist matches were near the 30 day cancellation deadline. I have entered waitlist request and received an email about a match within a week.
Owners love, love, love the waitlist, because it works so well. Club Wyndham owners who spend a lot of time searching for the same reservation over, and over, and over will be amazed at the convenience.