This could have been a fiasco. In fact, I am guilty of assuming, as soon as Don Giller announced he was stopping updating his channel and becoming a consultant for this official channel, that it would be a net loss for the fans. On the contrary, this has been an incredible resource, a channel that proves that sometimes there is value in "curation."
Every now and then, the channel does post full classic episodes, but it's mostly great vintage clips from the NBC and CBS years. However, it's not just clips. It is clear there is thought behind all of this. For example, they posted Darlene Love singing "Christmas (Baby, Please Come Home") this season, but they also put up a supercut of the annual show tradition over the years. Showing not just the singing but Letterman coming over each time and thanking her with apparent sincerity makes for a touching experience.
Clips are selected to match current events and occasions like holidays, but they also do other interesting things on the account. The running series of people involved with the show (mostly writers but others as well) is a highlight, with insightful comments and memories from the folks who were there. And of course every now and then Dave himself drops in for a brief comment or chat. Plus Giller shows up in the comments sometimes with tidbits and context. Overall, this is an essential for any fan and also a prolific, worthy tribute to the show's legacy