I have been a member on Ratebeer for several years and have rated numerous beers, plus meads and ciders. While I do this less than I did previously, I use it mainly as a means of cataloging different beers I've tried in my travels, but many people take it very seriously. I've found it and Beer Advocate to be good resources, but keep in mind that most people there are purely "beer geeks" who may not appreciate meads or ciders. Plenty of good mead gets rated poorly, while the super-sweet Polish meads do best (in the interest of full disclosure I do happen to love them as well). I think its important to understand that mead may not get the love it deserves on a beer or wine site and much of the rating/criticism may be as a result of not understanding the beverage.
Also keep in mind that these are largely user-driven sites (more so for Ratebeer, but also true for BeerAdvocate) and at least on Ratebeer, users "add" beers, meads, and ciders when they sample and rate them. In many ways I find this preferable to a brewer pushing for ratings of their product. That being said, there are many brewers who make their presence known on both sites and are available for discussion/questions, and I've usually appreciated receiving feedback from the brewer based on my rating.
Also keep in mind that it may take time to accumulate ratings, especially for brewers not located in higher traffic areas. Limited distribution will make getting your meads to more raters more difficult, though it should happen eventually!
