Following up on the beginner vs expert threat. Is there any work being done one establishing a reliable rating system for backgammon like the one that exists for chess?
A lot of questions of that type can be answered by a rating system. We know with a reasonable degree of accuracy what the expectation for players is in chess. And we also know where a particular player fits compared to others. For example: a 2100 player in the USA is better than about 91% of all players. But we also know that he has less than a 2% chance against a 2600 grandmaster. (maybe less than 1%)

Does a rating system exist for backgammon, and is it reliable?

The chess rating system was developed by Arpad Elo back in the 1950s, and it became known as the ELO system. It was first adopted by the US Chess Federation, then FIDE adopted it in the 1960s. It was also back-dated to develop historical ratings for players as far back as Morphy. The key feature of the system was constancy over the whole range; a 200-point rating difference predicted an identical winning probability for the higher rated player, no matter where the players were on the rating scale.

Kent Goulding implemented an ELO-based system for backgammon in the 1980s and kept it going for awhile, but lacked the manpower to maintain it and to collect all the tournament data you would want.

In the 1990s, the online site GamesGrid used an ELO system for rating its players. With an enormous amount of data available, it produced an internally consistent rating for its users, which included most of the world-class players of its day, as well as a broad section of players down to the beginner level. Newcomers started with an initial rating of 1500 and moved up or down from there quickly.

The rating scale that resulted was compressed compared to chess, reflecting the greater skill to chance ratio for chess. Chess ratings range from 3100 (Rybka) to zero or slightly negative for beginners. The GamesGrid backgammon ratings covered a scale from about 1000 for beginners to 2050 or so for world-class players.

GG is now defunct, and the trend on online BG sites is away from ratings (they suppress action). No formal rating system exists for BG players right now.

There is a widely used ELO for backgammon, as first implemented by FIBS. The FIBS home page(not the game server) will point you toward the particulars. If you examine the ratings on the game server, you will see similar bots with very similar ratings.