I've gone on about this topic in the comments to Tim's post from earlier this week, but here's another example from the Smithsonian in today's Wash Post - "Going to Meet Its Public: Indian Museum Will Put Entire Collection Online," By Jacqueline Trescott, Washington Post Staff Writer, Friday, January 30, 2009; Page C01.
This Museum has a built-in lead - they were moved down to Washington recently (in Museum terms) and I'm sure they had excellent records and photos created at that time. When they set up the Museum, they decided to forego exhibit labels in the cases and instead provided a computer screen in front of the exhibit where you could look up what you were actually looking at (I despised this, because only 1 person at a time could look at an exhibit label and I didn't understand why they didn't just put that on the web back then).
So even with a running start, we read "The online project, part of the museum's regular Web site, will begin with 5,500 items and photographs. The goal is to have all 800,000 objects on the Web site, but it will take at least four years to achieve that. ... The museum has raised $750,000 for the first four years of the project, and Gover said a deadline has not been set for the Fourth Museum completion."
So that long tail takes a while to get long enough to trail off...